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+</style><link href="http://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css" charset="utf-8" /></head>
+
+ <body style="display: inherit; "><div class="head"><p><a href="http://www.w3.org/"><img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" /></a></p><h1 property="dcterms:title" class="title" id="title">RDF 1.1 Concepts and Abstract Syntax</h1><h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-01-15T00:00:00+0000" id="w3c-working-draft-15-january-2013"><acronym title="World Wide Web Consortium">W3C</acronym> Working Draft 15 January 2013</h2><dl><dt>This version:</dt><dd><a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/">http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/</a></dd><dt>Latest published version:</dt><dd><a href="http://www.w3.org/TR/rdf11-concepts/">http://www.w3.org/TR/rdf11-concepts/</a></dd><dt>Latest editor's draft:</dt><dd><a href="http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html">http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html</a></dd><dt>Previous version:</dt><dd><a rel="dcterms:replaces" href="http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/">http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/</a></dd><dt>Latest recommendation:</dt><dd><a href="http://www.w3.org/TR/rdf-concepts/">http://www.w3.org/TR/rdf-concepts/</a></dd><dt>Editors:</dt><dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Richard Cyganiak" href="http://richard.cyganiak.de/">Richard Cyganiak</a>, <a rel="foaf:workplaceHomepage" href="http://www.deri.ie/">DERI, NUI Galway</a></span>
+</dd>
+<dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><span property="foaf:name">David Wood</span>, <a rel="foaf:workplaceHomepage" href="http://www.3roundstones.com/">3 Round Stones</a></span>
+</dd>
+<dt>Previous editors:</dt><dd><span><span>Graham Klyne</span>, Nine by Nine</span>
+</dd>
+<dd><span><span>Jeremy J. Carroll</span>, Hewlett Packard Labs</span>
+</dd>
+<dd><span><span>Brian McBride</span>, Hewlett Packard Labs (RDF 2004 Series Editor)</span>
+</dd>
+</dl><p class="copyright"><a rel="license" href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2004-2013 <span rel="dcterms:publisher"><span typeof="foaf:Organization"><a rel="foaf:homepage" property="foaf:name" content="World Wide Web Consortium" href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup></span></span> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. <acronym title="World Wide Web Consortium">W3C</acronym> <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p><hr /></div>
+
+<div id="abstract" class="introductory section" property="dcterms:abstract" datatype="" typeof="bibo:Chapter" resource="#abstract" rel="bibo:chapter"><h2>Abstract</h2>
+ <p>The Resource Description Framework (RDF) is a framework for
+ representing information in the Web.</p>
+ <p>RDF 1.1 Concepts and Abstract Syntax defines an abstract syntax
+ (a data model) which serves to link all RDF-based languages and
+ specifications. The abstract syntax has two key data structures:
+ RDF graphs are sets of subject-predicate-object triples,
+ where the elements may be IRIs, blank nodes, or datatyped literals. They
+ are used to express descriptions of resources. RDF datasets are used
+ to organize collections of RDF graphs, and comprise a default graph
+ and zero or more named graphs.
+ This document also introduces key concepts and terminology, and discusses
+ datatyping and the handling of fragment identifiers in IRIs within
+ RDF graphs.</p>
+</div><div id="sotd" class="introductory section" typeof="bibo:Chapter" resource="#sotd" rel="bibo:chapter"><h2>Status of This Document</h2><p><em>This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current <acronym title="World Wide Web Consortium">W3C</acronym> publications and the latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/"><acronym title="World Wide Web Consortium">W3C</acronym> technical reports index</a> at http://www.w3.org/TR/.</em></p>
+ <p>This document is a snapshot of the
+ <a href="http://www.w3.org/2011/rdf-wg/">RDF Working Group</a>'s
+ progress towards updating the RDF data model for RDF 1.1.
+ A <a href="#changes-wd3">list of changes</a> since the
+ <a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20120605/">previous working draft</a>
+ is provided as an appendix.
+ The most significant normative change in this Working Draft
+ is the adoption of the concepts of
+ <a href="#section-dataset">RDF Dataset</a> and
+ <a href="#dfn-named-graph">named graph</a> from
+ <a href="http://www.w3.org/TR/sparql11-query/">SPARQL</a>.
+ The <a href="#section-Introduction">introduction</a> has seen
+ major changes, as have various informative notes
+ throughout the document.
+ Various areas of ongoing work are marked throughout the text,
+ in particular the definitions of
+ <a href="#section-blank-nodes">blank nodes</a>,
+ <a href="#dfn-ill-typed">ill-typed literals</a>,
+ <a href="#section-dataset">operations on RDF datasets</a>,
+ and the <a href="#section-fragID">relation of RDF datasets to
+ aspects of web architecture</a>.</p>
+<p>This document was published by the <a href="http://www.w3.org/2011/rdf-wg/">RDF Working Group</a> as a Working Draft. This document is intended to become a <acronym title="World Wide Web Consortium">W3C</acronym> Recommendation. If you wish to make comments regarding this document, please send them to <a href="mailto:public-rdf-comments@w3.org">public-rdf-comments@w3.org</a> (<a href="mailto:public-rdf-comments-request@w3.org?subject=subscribe">subscribe</a>, <a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">archives</a>). All feedback is welcome.</p><p>Publication as a Working Draft does not imply endorsement by the <acronym title="World Wide Web Consortium">W3C</acronym> Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.</p><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <acronym title="World Wide Web Consortium">W3C</acronym> Patent Policy</a>. <acronym title="World Wide Web Consortium">W3C</acronym> maintains a <a href="http://www.w3.org/2004/01/pp-impl/46168/status" rel="disclosure">public list of any patent disclosures</a> made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the <acronym title="World Wide Web Consortium">W3C</acronym> Patent Policy</a>.</p></div><div id="toc" typeof="bibo:Chapter" resource="#toc" rel="bibo:chapter" class="section"><h2 class="introductory">Table of Contents</h2><ul class="toc"><li class="tocline"><a href="#section-Introduction" class="tocxref"><span class="secno">1 </span>Introduction</a><ul class="toc"><li class="tocline"><a href="#data-model" class="tocxref"><span class="secno">1.1 </span>Graph-based Data Model</a></li><li class="tocline"><a href="#resources-and-statements" class="tocxref"><span class="secno">1.2 </span>Resources and Statements</a></li><li class="tocline"><a href="#referents" class="tocxref"><span class="secno">1.3 </span>The Referent of an <acronym title="Internationalized Resource Identifier">IRI</acronym></a></li><li class="tocline"><a href="#vocabularies" class="tocxref"><span class="secno">1.4 </span>RDF Vocabularies and Namespace IRIs</a></li><li class="tocline"><a href="#change-over-time" class="tocxref"><span class="secno">1.5 </span>RDF and Change Over Time</a></li><li class="tocline"><a href="#managing-graphs" class="tocxref"><span class="secno">1.6 </span>Working with Multiple RDF Graphs</a></li><li class="tocline"><a href="#entailment" class="tocxref"><span class="secno">1.7 </span>Equivalence, Entailment and Inconsistency</a></li><li class="tocline"><a href="#rdf-documents" class="tocxref"><span class="secno">1.8 </span>RDF Documents and Syntaxes</a></li></ul></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">2 </span>Conformance</a></li><li class="tocline"><a href="#section-rdf-graph" class="tocxref"><span class="secno">3 </span>RDF Graphs</a><ul class="toc"><li class="tocline"><a href="#section-triples" class="tocxref"><span class="secno">3.1 </span>Triples</a></li><li class="tocline"><a href="#section-IRIs" class="tocxref"><span class="secno">3.2 </span>IRIs</a></li><li class="tocline"><a href="#section-Graph-Literal" class="tocxref"><span class="secno">3.3 </span>Literals</a></li><li class="tocline"><a href="#section-blank-nodes" class="tocxref"><span class="secno">3.4 </span>Blank Nodes</a></li><li class="tocline"><a href="#section-skolemization" class="tocxref"><span class="secno">3.5 </span>Replacing Blank Nodes with IRIs</a></li><li class="tocline"><a href="#graph-isomorphism" class="tocxref"><span class="secno">3.6 </span>Graph Isomorphism</a></li></ul></li><li class="tocline"><a href="#section-dataset" class="tocxref"><span class="secno">4 </span>RDF Datasets</a></li><li class="tocline"><a href="#section-Datatypes" class="tocxref"><span class="secno">5 </span>Datatypes</a><ul class="toc"><li class="tocline"><a href="#xsd-datatypes" class="tocxref"><span class="secno">5.1 </span>The XML Schema Built-in Datatypes</a></li><li class="tocline"><a href="#section-html" class="tocxref"><span class="secno">5.2 </span>The <code>rdf:HTML</code> Datatype</a></li><li class="tocline"><a href="#section-XMLLiteral" class="tocxref"><span class="secno">5.3 </span>The <code>rdf:XMLLiteral</code> Datatype</a></li><li class="tocline"><a href="#datatype-maps" class="tocxref"><span class="secno">5.4 </span>Datatype Maps</a></li><li class="tocline"><a href="#section-Literal-Value" class="tocxref"><span class="secno">5.5 </span>The Value Corresponding to a Literal</a></li></ul></li><li class="tocline"><a href="#section-fragID" class="tocxref"><span class="secno">6 </span>Fragment Identifiers</a></li><li class="tocline"><a href="#section-Acknowledgments" class="tocxref"><span class="secno">7 </span>Acknowledgments</a></li><li class="tocline"><a href="#changes" class="tocxref"><span class="secno">A </span>Changes between RDF 2004 and RDF 1.1</a></li><li class="tocline"><a href="#change-log" class="tocxref"><span class="secno">B </span>Change Log</a><ul class="toc"><li class="tocline"><a href="#changes-wd3" class="tocxref"><span class="secno">B.1 </span>Changes from 05 June 2012 WD to this version</a></li><li class="tocline"><a href="#changes-wd2" class="tocxref"><span class="secno">B.2 </span>Changes from FPWD to 05 June 2012 WD</a></li><li class="tocline"><a href="#changes-fpwd" class="tocxref"><span class="secno">B.3 </span>Changes from RDF 2004 to FPWD</a></li></ul></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></div>
+
+
+
+
+
+<div id="section-Introduction" class="informative section" typeof="bibo:Chapter" resource="#section-Introduction" rel="bibo:chapter">
+ <h2><span class="secno">1 </span>Introduction</h2><p><em>This section is non-normative.</em></p>
+
+ <p class="issue">This is a work-in-progress Working Draft. Various open
+ issues are flagged throughout the text with boxes like this.
+ <a href="#sotd">Feedback</a> on these issues is particularly welcome.</p>
+
+ <p>The <em>Resource Description Framework</em> (RDF) is a framework
+ for representing information in the Web.</p>
+
+ <p>This document defines an abstract syntax (a data model)
+ which serves to link all RDF-based languages and specifications,
+ including:</p>
+
+ <ul>
+ <li>serialization syntaxes for storing and exchanging RDF
+ (e.g., <a href="http://www.w3.org/TR/turtle/">Turtle</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE-TR">TURTLE-TR</a></cite>]
+ and <a href="http://www.w3.org/TR/REC-rdf-syntax/">RDF/XML</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>]),</li>
+
+ <li>the <a href="http://www.w3.org/TR/rdf-sparql-query/">SPARQL
+ Query Language</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SPARQL-QUERY">RDF-SPARQL-QUERY</a></cite>],</li>
+
+ <li>the <a href="http://www.w3.org/TR/rdf-schema/">RDF Vocabulary
+ Description Language</a> (RDFS) [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>],</li>
+
+ <li>the <a href="http://www.w3.org/TR/rdf-mt/">formal
+ model-theoretic semantics for RDF and RDFS</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>].</li>
+ </ul>
+
+<div id="data-model" typeof="bibo:Chapter" resource="#data-model" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.1 </span>Graph-based Data Model</h3>
+
+ <p>The core structure of the abstract syntax is a set of
+ <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a>, each consisting of a <a href="#dfn-subject" class="internalDFN">subject</a>,
+ a <a href="#dfn-predicate" class="internalDFN">predicate</a> and an <a href="#dfn-object" class="internalDFN">object</a>. A set of such triples is called
+ an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>. An RDF graph can be visualized as a node and
+ directed-arc diagram, in which each triple is represented as a
+ node-arc-node link.</p>
+
+ <div class="figure">
+ <a href="rdf-graph.png"><img src="rdf-graph.svg" alt="An RDF graph with two nodes (Subject and Object) and a triple connecting them (Predicate)" /></a>
+ </div>
+
+ <p>There can be three kinds of <a title="node" href="#dfn-node" class="internalDFN">nodes</a> in an
+ <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>: <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>,
+ and <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a>.</p>
+</div>
+
+
+<div id="resources-and-statements" typeof="bibo:Chapter" resource="#resources-and-statements" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.2 </span>Resources and Statements</h3>
+
+ <p>Any <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> or <a href="#dfn-literal" class="internalDFN">literal</a> <dfn title="denote" id="dfn-denote">denotes</dfn>
+ some thing in the universe of discourse. These things are called
+ <dfn title="resource" id="dfn-resource">resources</dfn>. Anything can be a resource,
+ including physical things, documents, abstract concepts, numbers
+ and strings; the term is synonymous with “entity”.
+ The resource denoted by an <acronym title="Internationalized Resource Identifier">IRI</acronym> is called its <a href="#dfn-referent" class="internalDFN">referent</a>, and the
+ resource denoted by a literal is called its
+ <a title="literal value" href="#dfn-literal-value" class="internalDFN">literal value</a>. Literals have
+ <a title="datatype" href="#dfn-datatype" class="internalDFN">datatypes</a> that define the range of possible
+ values, such as strings, numbers, and dates. A special kind of literals,
+ <a>language-tagged strings</a>, denote plain-text strings in a
+ natural language.</p>
+
+ <p>The assertion of an <a href="#dfn-rdf-triple" class="internalDFN">RDF triple</a> says that <em>some relationship,
+ indicated by the <a href="#dfn-predicate" class="internalDFN">predicate</a>, holds between the
+ <a title="resource" href="#dfn-resource" class="internalDFN">resources</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by
+ the <a href="#dfn-subject" class="internalDFN">subject</a> and <a href="#dfn-object" class="internalDFN">object</a></em>. This statement corresponding
+ to an RDF triple is known as an <dfn id="dfn-rdf-statement">RDF statement</dfn>.
+ The predicate itself is an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> and denotes a <dfn id="dfn-property">property</dfn>,
+ that is, a <a href="#dfn-resource" class="internalDFN">resource</a> that can be thought of as a binary relation.
+ (Relations that involve more than two entities can only be
+ <a href="http://www.w3.org/TR/swbp-n-aryRelations/">indirectly
+ expressed in RDF</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-SWBP-N-ARYRELATIONS">SWBP-N-ARYRELATIONS</a></cite>].)</p>
+
+ <p>Unlike <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>,
+ <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a> do not denote specific
+ <a title="resource" href="#dfn-resource" class="internalDFN">resources</a>.
+ <a title="RDF statement" href="#dfn-rdf-statement" class="internalDFN">Statements</a> involving
+ blank nodes say that something with the given
+ relationships exists, without explicitly naming it.</p>
+</div>
+
+
+<div id="referents" typeof="bibo:Chapter" resource="#referents" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.3 </span>The Referent of an <acronym title="Internationalized Resource Identifier">IRI</acronym></h3>
+
+ <p>The <a href="#dfn-resource" class="internalDFN">resource</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>
+ is also called its <dfn id="dfn-referent">referent</dfn>.
+ What exactly is denoted by any given <acronym title="Internationalized Resource Identifier">IRI</acronym> is not defined by this
+ specification.</p>
+
+ <p>Guidelines for determining the <a href="#dfn-referent" class="internalDFN">referent</a> of an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> are
+ provided in other documents, like
+ <em><a href="http://www.w3.org/TR/webarch/">Architecture of the
+ World Wide Web, Volume One</a></em> [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] and
+ <em><a href="http://www.w3.org/TR/cooluris/">Cool URIs for the
+ Semantic Web</a></em> [<cite><a class="bibref" rel="biblioentry" href="#bib-COOLURIS">COOLURIS</a></cite>].
+ A very brief, informal and partial account follows:</p>
+
+ <ul>
+ <li>IRIs have global scope: An <acronym title="Internationalized Resource Identifier">IRI</acronym> is assumed to <a href="#dfn-denote" class="internalDFN">denote</a>
+ the same <a href="#dfn-resource" class="internalDFN">resource</a> regardless of where the <acronym title="Internationalized Resource Identifier">IRI</acronym> occurs.</li>
+
+ <li>By social convention, the
+ <a href="http://www.w3.org/TR/webarch/#uri-ownership"><acronym title="Internationalized Resource Identifier">IRI</acronym> owner</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] gets to say what an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> <a title="denote" href="#dfn-denote" class="internalDFN">denotes</a>.
+ They do this when “<dfn id="dfn-minting">minting</dfn>” a new <acronym title="Internationalized Resource Identifier">IRI</acronym>.</li>
+
+ <li>The <acronym title="Internationalized Resource Identifier">IRI</acronym> owner can establish the intended <a href="#dfn-referent" class="internalDFN">referent</a>
+ by means of a specification or other document that explains
+ what is denoted. For example, the
+ <a href="http://www.w3.org/TR/vocab-org/">Organization Ontology
+ document</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-VOCAB-ORG">VOCAB-ORG</a></cite>] specifies the referents
+ of various IRIs that start with
+ <code>http://www.w3.org/ns/org#</code>.</li>
+
+ <li>A good way of communicating the intended referent
+ is to set up the <acronym title="Internationalized Resource Identifier">IRI</acronym> so that it
+ <a href="http://www.w3.org/TR/webarch/#uri-dereference">dereferences</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] to such a document.</li>
+
+ <li>Such a document can, in fact, be an <a href="#dfn-rdf-document" class="internalDFN">RDF document</a>
+ that describes the denoted resource by means of
+ <a title="RDF statement" href="#dfn-rdf-statement" class="internalDFN">RDF statements</a>.</li>
+ </ul>
+
+ <p>Perhaps the most important characterisitic of <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>
+ in web architecture is that they can be
+ <a href="http://www.w3.org/TR/webarch/#uri-dereference">dereferenced</a>,
+ and hence serve as starting points for interactions with a remote server.
+ This specification, however, is not concerned with such interactions.
+ It does not define an interaction model. It only treats IRIs as globally
+ unique identifiers in a graph data model that describes resources.</p>
+</div>
+
+<div id="vocabularies" typeof="bibo:Chapter" resource="#vocabularies" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.4 </span>RDF Vocabularies and Namespace IRIs</h3>
+
+ <p>An <dfn id="dfn-rdf-vocabulary">RDF vocabulary</dfn> is a collection of <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>
+ with clearly established <a title="referent" href="#dfn-referent" class="internalDFN">referents</a>
+ intended for use in <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. For example,
+ the IRIs documented in [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>] are the RDF Schema vocabulary.
+ RDF Schema can itself be used to define and document additional
+ RDF vocabularies. Some such vocabularies are mentioned in the
+ Primer [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-PRIMER">RDF-PRIMER</a></cite>].</p>
+
+ <p>The <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> in an <a href="#dfn-rdf-vocabulary" class="internalDFN">RDF vocabulary</a> often share
+ a common substring known as a <dfn id="dfn-namespace-iri">namespace <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>.
+ Some namespace IRIs are associated by convention with a short name
+ known as a <dfn id="dfn-namespace-prefix">namespace prefix</dfn>. Some examples:
+
+ </p><table rules="all" summary="Some example namespace prefixes and IRIs">
+ <tbody><tr><th>Namespace prefix</th><th>Namespace <acronym title="Internationalized Resource Identifier">IRI</acronym></th><th>RDF vocabulary</th></tr>
+ <tr><td>rdf</td><td><a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><code>http://www.w3.org/1999/02/22-rdf-syntax-ns#</code></a></td><td>The RDF built-in vocabulary [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]</td></tr>
+ <tr><td>rdfs</td><td><a href="http://www.w3.org/2000/01/rdf-schema#"><code>http://www.w3.org/2000/01/rdf-schema#</code></a></td><td>The RDF Schema vocabulary [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]</td></tr>
+ <tr><td>xsd</td><td><a href="http://www.w3.org/2001/XMLSchema#"><code>http://www.w3.org/2001/XMLSchema#</code></a></td><td>The <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a></td></tr>
+ </tbody></table>
+
+ <p>In some contexts it is common to abbreviate <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>
+ that start with <a title="namespace IRI" href="#dfn-namespace-iri" class="internalDFN">namespace IRIs</a> by using the
+ associated <a href="#dfn-namespace-prefix" class="internalDFN">namespace prefix</a>. For example, the <acronym title="Internationalized Resource Identifier">IRI</acronym>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>
+ would be abbreviated as <code>rdf:XMLLiteral</code>.
+ Note however that these abbreviations are <em>not</em> valid IRIs,
+ and must not be used in contexts where IRIs are expected.
+ Namespace IRIs and namespace prefixes are <em>not</em> a formal part of the
+ RDF data model. They are merely a syntactic convenience for
+ abbreviating IRIs.</p>
+
+ <p>The term “<dfn id="dfn-namespace">namespace</dfn>” on its own does not have a
+ well-defined meaning in the context of RDF, but is sometimes informally
+ used to mean “<a href="#dfn-namespace-iri" class="internalDFN">namespace <acronym title="Internationalized Resource Identifier">IRI</acronym></a>” or “<a href="#dfn-rdf-vocabulary" class="internalDFN">RDF vocabulary</a>”.</p>
+</div>
+
+
+<div id="change-over-time" typeof="bibo:Chapter" resource="#change-over-time" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.5 </span>RDF and Change Over Time</h3>
+
+ <p>The RDF data model is <em>atemporal</em>: It does not deal with time,
+ and does not have a built-in notion of temporal validity of information.
+ <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> are static snapshots of
+ information.</p>
+
+ <p>However, <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> can express information
+ about events and about temporal aspects of other entities,
+ given appropriate <a title="RDF vocabulary" href="#dfn-rdf-vocabulary" class="internalDFN">vocabulary</a> terms.</p>
+
+ <p>Since <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> are defined as mathematical
+ sets, adding or removing <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a> from an
+ RDF graph yields a different RDF graph.</p>
+
+ <p>We informally use the term <dfn id="dfn-rdf-source">RDF source</dfn> to refer to a
+ persistent yet mutable source or container of
+ <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. An RDF source is a <a href="#dfn-resource" class="internalDFN">resource</a>
+ that may be said to have a state that can change over time.
+ A snapshot of the state can be expressed as an RDF graph.
+ For example, any web document that has an RDF-bearing representation
+ may be considered an RDF source. Like all resources, RDF sources may
+ be named with <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and therefore described in
+ other RDF graphs.</p>
+
+ <p>Intuitively speaking, changes in the universe of discourse
+ can be reflected in the following ways:</p>
+
+ <ul>
+ <li>An <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>, once <a title="minting" href="#dfn-minting" class="internalDFN">minted</a>, should never
+ change its <a href="#dfn-referent" class="internalDFN">referent</a>. (See
+ <a href="http://www.w3.org/TR/webarch/#URI-persistence"><acronym title="Uniform Resource Identifier">URI</acronym>
+ persistence</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>].)</li>
+ <li><a title="literal" href="#dfn-literal" class="internalDFN">Literals</a>, by design, are constants and
+ never change their <a title="literal value" href="#dfn-literal-value" class="internalDFN">value</a>.</li>
+ <li>Some <a title="property" href="#dfn-property" class="internalDFN">properties</a> may change over time.
+ A relationship that holds between two <a title="resource" href="#dfn-resource" class="internalDFN">resources</a>
+ at one time may not hold at another time.</li>
+ <li><a title="RDF source" href="#dfn-rdf-source" class="internalDFN">RDF sources</a> may change their state
+ over time.
+ That is, they may provide different <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>
+ at different times.</li>
+ <li>Some <a title="RDF source" href="#dfn-rdf-source" class="internalDFN">RDF sources</a> may, however, be immutable
+ snapshots of another RDF source, archiving its state at some
+ point in time.</li>
+ </ul>
+
+</div>
+
+
+<div id="managing-graphs" typeof="bibo:Chapter" resource="#managing-graphs" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.6 </span>Working with Multiple RDF Graphs</h3>
+
+ <p>As RDF graphs are sets of triples, they can be
+ <a title="merge" href="#dfn-merge" class="internalDFN">merged</a> easily, supporting the use of data from
+ multiple sources. Nevertheless, it is sometimes desirable to work
+ with multiple RDF graphs while keeping their contents separate.
+ <a title="RDF dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a> support this requirement.</p>
+
+ <p>An <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a> is a collection of
+ <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. All but one of these graphs have
+ an associated <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>. They are called
+ <a title="named graph" href="#dfn-named-graph" class="internalDFN">named graphs</a>, and the <acronym title="Internationalized Resource Identifier">IRI</acronym> is called the
+ <a href="#dfn-graph-name" class="internalDFN">graph name</a>.
+ The remaining graph does not have an associated <acronym title="Internationalized Resource Identifier">IRI</acronym>, and is called
+ the <a href="#dfn-default-graph" class="internalDFN">default graph</a> of the RDF dataset.</p>
+
+ <p>There are many possible uses for <a title="RDF dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a>.
+ One such use is to hold snapshots of multiple
+ <a title="RDF source" href="#dfn-rdf-source" class="internalDFN">RDF sources</a>. It is common to have the
+ <a href="#dfn-default-graph" class="internalDFN">default graph</a> contain <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a>
+ that involve the <a title="graph name" href="#dfn-graph-name" class="internalDFN">graph names</a>
+ of the other graphs in the dataset.</p>
+</div>
+
+
+<div id="entailment" typeof="bibo:Chapter" resource="#entailment" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.7 </span>Equivalence, Entailment and Inconsistency</h3>
+
+ <p class="issue">No Editor's Draft of <em>RDF 1.1 Semantics</em> is
+ available yet
+ (<a href="https://www.w3.org/2011/rdf-wg/track/actions/214">ACTION-214</a>),
+ and its relationship to this document is not yet
+ entirely clear. Some Semantics-related material may be moved here,
+ in particular the definition of <dfn title="merge" id="dfn-merge">graph merge</dfn> and
+ <dfn id="dfn-subgraph">subgraph</dfn>, and informative
+ <a href="http://www.w3.org/TR/rdf-mt/#rules">entailment rules</a>
+ for the entailments over the RDF data model
+ (excluding any specific vocabulary). This is
+ <a href="https://www.w3.org/2011/rdf-wg/track/issues/106">ISSUE-106</a>.</p>
+
+ <p class="issue">The Working Group intends to publish a Working Group
+ Note detailing some of its efforts to define a <strong>formal semantics for
+ RDF datasets</strong>. It should be referenced here when available. This is
+ <a href="http://www.w3.org/2011/rdf-wg/track/actions/209">ACTION-209</a>.
+ </p>
+
+ <p>An <a href="#dfn-rdf-triple" class="internalDFN">RDF triple</a> encodes a <a title="RDF statement" href="#dfn-rdf-statement" class="internalDFN">statement</a>—a
+ simple <dfn id="dfn-logical-expression">logical expression</dfn>, or claim about the world.
+ An <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> is the conjunction (logical <em>AND</em>) of
+ its triples, and the conjunction of two RDF graphs is their <a href="#dfn-merge" class="internalDFN">merge</a>.
+ This treatment of RDF graphs as logical expressions is
+ normatively defined in the
+ <a href="http://www.w3.org/TR/rdf-mt/">RDF Semantics</a>
+ specification [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>], using a model-theoretic semantics.
+ It yields various relationships between RDF graphs:</p>
+
+ <dl>
+ <dt><dfn id="dfn-entailment">Entailment</dfn></dt>
+ <dd>An <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> <em>A</em> entails another RDF graph <em>B</em>
+ if every possible arrangement of the world
+ that makes <em>A</em> true also makes <em>B</em> true. When <em>A</em>
+ entails <em>B</em>, if the truth of <em>A</em> is presumed or demonstrated
+ then the truth of <em>B</em> is established.</dd>
+
+ <dt><dfn id="dfn-equivalence">Equivalence</dfn></dt>
+ <dd>Two <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> <em>A</em> and <em>B</em>
+ are equivalent if they make the same claim about the world.
+ <em>A</em> is equivalent to <em>B</em> if and only if
+ <em>A</em> <a title="entailment" href="#dfn-entailment" class="internalDFN">entails</a> <em>B</em> and
+ <em>B</em> entails <em>A</em>.</dd>
+
+ <dt><dfn id="dfn-inconsistency">Inconsistency</dfn></dt>
+ <dd>An <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> is inconsistent if it contains
+ an internal contradiction. There is no possible arrangement
+ of the world that would make the expression true.</dd>
+ </dl>
+
+ <p>An <dfn id="dfn-entailment-regime">entailment regime</dfn> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>] is a specification that
+ defines precise conditions that make these relationships hold.
+ RDF itself recognizes only some basic cases of entailment, equivalence
+ and inconsistency. Other specifications, such as
+ <a href="http://www.w3.org/TR/rdf-schema/">RDF Schema</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]
+ and <a href="http://www.w3.org/TR/owl2-overview/">OWL 2</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>], add more powerful entailment regimes,
+ as do some domain-specific <a title="RDF vocabulary" href="#dfn-rdf-vocabulary" class="internalDFN">vocabularies</a>.
+ Some entailment regimes are defined with respect to a
+ <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>.</p>
+
+ <p>This specification does not constrain how implementations
+ use the logical relationships defined by
+ <a title="entailment regime" href="#dfn-entailment-regime" class="internalDFN">entailment regimes</a>.
+ Implementations may or may not detect
+ <a title="inconsistency" href="#dfn-inconsistency" class="internalDFN">inconsistencies</a>, and may make all,
+ some or no <a title="entailment" href="#dfn-entailment" class="internalDFN">entailed</a> information
+ available to users.</p>
+</div>
+
+
+<div id="rdf-documents" typeof="bibo:Chapter" resource="#rdf-documents" rel="bibo:chapter" class="section">
+ <h3><span class="secno">1.8 </span>RDF Documents and Syntaxes</h3>
+
+ <p>An <dfn id="dfn-rdf-document">RDF document</dfn> is a document that encodes an
+ <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> or <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a> in a <dfn id="dfn-concrete-rdf-syntax">concrete RDF syntax</dfn>,
+ such as Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE-TR">TURTLE-TR</a></cite>], RDFa [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-PRIMER">RDFA-PRIMER</a></cite>],
+ RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>], or N-Triples [<cite><a class="bibref" rel="biblioentry" href="#bib-N-TRIPLES">N-TRIPLES</a></cite>].
+ RDF documents enable the exchange of RDF graphs and RDF datasets
+ between systems.</p>
+
+ <p>A <a href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntax</a><a> may offer
+ many different ways to encode the same </a><a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> or
+ <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>, for example through the use of
+ <a title="namespace prefix" href="#dfn-namespace-prefix" class="internalDFN">namespace prefixes</a>,
+ relative IRIs, <a title="blank node identifier" href="#dfn-blank-node-identifier" class="internalDFN">blank node identifiers</a>,
+ and different ordering of statements. While these aspects can have great
+ effect on the convenience of working with the <a href="#dfn-rdf-document" class="internalDFN">RDF document</a>,
+ they are not significant for its meaning.</p>
+</div>
+
+
+</div>
+
+
+<div id="conformance" typeof="bibo:Chapter" resource="#conformance" rel="bibo:chapter" class="section"><h2><span class="secno">2 </span>Conformance</h2><p>As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.</p>
+<p>The key words <em class="rfc2119" title="must">must</em>, <em class="rfc2119" title="must not">must not</em>, <em class="rfc2119" title="required">required</em>, <em class="rfc2119" title="should">should</em>, <em class="rfc2119" title="should not">should not</em>, <em class="rfc2119" title="recommended">recommended</em>, <em class="rfc2119" title="may">may</em>, and <em class="rfc2119" title="optional">optional</em> in this specification are to be interpreted as described in [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC2119">RFC2119</a></cite>].</p>
+
+ <p>This specification, <em>RDF 1.1 Concepts and Abstract Syntax</em>,
+ defines a data model and related terminology for use in
+ other specifications, such as
+ <a title="concrete RDF syntax" href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntaxes</a>,
+ API specifications, and query languages.
+ Implementations cannot directly conform to
+ <em>RDF 1.1 Concepts and Abstract Syntax</em>,
+ but can conform to such other specifications that normatively
+ reference terms defined here.</p>
+</div>
+
+
+<div id="section-rdf-graph" typeof="bibo:Chapter" resource="#section-rdf-graph" rel="bibo:chapter" class="section">
+ <h2><span class="secno">3 </span>RDF Graphs</h2>
+
+ <p>An <dfn id="dfn-rdf-graph">RDF graph</dfn> is a set of
+ <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">RDF triples</a>.</p>
+
+
+<div id="section-triples" typeof="bibo:Chapter" resource="#section-triples" rel="bibo:chapter" class="section">
+ <h3><span class="secno">3.1 </span>Triples</h3>
+
+ <p>An <dfn id="dfn-rdf-triple">RDF triple</dfn> consists of three components:</p>
+
+ <ul>
+ <li>the <dfn id="dfn-subject">subject</dfn>, which is an
+ <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> or a <a href="#dfn-blank-node" class="internalDFN">blank node</a></li>
+
+ <li>the <dfn id="dfn-predicate">predicate</dfn>, which is an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a></li>
+
+ <li>the <dfn id="dfn-object">object</dfn>, which is an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>,
+ a <a href="#dfn-literal" class="internalDFN">literal</a> or a <a href="#dfn-blank-node" class="internalDFN">blank node</a></li>
+ </ul>
+
+ <p>An RDF triple is conventionally written in the order subject,
+ predicate, object.</p>
+
+ <p>The set of <dfn title="node" id="dfn-node">nodes</dfn> of an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>
+ is the set of subjects and objects of triples in the graph.
+ It is possible for a predicate <acronym title="Internationalized Resource Identifier">IRI</acronym> to also occur as a node in
+ the same graph.</p>
+
+ <p><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> and
+ <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a> are collectively known as
+ <dfn title="RDF term" id="dfn-rdf-term">RDF terms</dfn>.</p>
+
+ <p class="note"><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>
+ and <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a> are distinct and distinguishable.
+ For example, <code>http://example.org/</code> as a string literal
+ is not equal to <code>http://example.org/</code> as an <acronym title="Internationalized Resource Identifier">IRI</acronym>,
+ nor to a blank node with the <a href="#dfn-blank-node-identifier" class="internalDFN">blank node identifier</a>
+ <code>http://example.org/</code>.</p>
+</div>
+
+
+<div id="section-IRIs" typeof="bibo:Chapter" resource="#section-IRIs" rel="bibo:chapter" class="section">
+ <h3><span class="secno">3.2 </span>IRIs</h3>
+
+ <p>An <dfn title="IRI" id="dfn-iri"><acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>
+ (Internationalized Resource Identifier) within an RDF graph
+ is a Unicode string [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] that conforms to the syntax
+ defined in RFC 3987 [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>].</p>
+
+ <p>IRIs in the RDF abstract syntax <em class="rfc2119" title="must">must</em> be absolute, and <em class="rfc2119" title="may">may</em>
+ contain a fragment identifier.</p>
+
+ <p><dfn id="dfn-iri-equality"><acronym title="Internationalized Resource Identifier">IRI</acronym> equality</dfn>:
+ Two IRIs are equal if and only if they are equivalent
+ under Simple String Comparison according to
+ <a href="http://tools.ietf.org/html/rfc3987#section-5.1">section 5.1</a>
+ of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. Further normalization <em class="rfc2119" title="must not">must not</em> be performed when
+ comparing IRIs for equality.</p>
+
+ <div class="note" id="note-iris">
+ <p><strong>URIs and IRIs:</strong>
+ IRIs are a generalization of
+ <dfn title="URI" id="dfn-uri"><acronym title="Uniform Resource Identifier">URI</acronym>s</dfn> [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>] that permits a much wider range of Unicode characters.
+ Every absolute <acronym title="Uniform Resource Identifier">URI</acronym> and URL is an <acronym title="Internationalized Resource Identifier">IRI</acronym>, but not every <acronym title="Internationalized Resource Identifier">IRI</acronym> is an <acronym title="Uniform Resource Identifier">URI</acronym>.
+ When IRIs are used in operations that are only
+ defined for URIs, they must first be converted according to
+ the mapping defined in
+ <a href="http://tools.ietf.org/html/rfc3987#section-3.1">section 3.1</a>
+ of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. A notable example is retrieval over the HTTP
+ protocol. The mapping involves UTF-8 encoding of non-ASCII
+ characters, %-encoding of octets not allowed in URIs, and
+ Punycode-encoding of domain names.</p>
+
+ <p><strong>Relative IRIs:</strong>
+ Some <a title="concrete RDF syntax" href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntaxes</a> permit
+ <dfn title="relative IRI" id="dfn-relative-iri">relative IRIs</dfn> as a convenient shorthand
+ that allows authoring of documents independently from their final
+ publishing location. Relative IRIs must be
+ <a href="http://tools.ietf.org/html/rfc3986#section-5.2">resolved
+ against</a> a <dfn id="dfn-base-iri">base <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn> to make them absolute.
+ Therefore, the RDF graph serialized in such syntaxes is well-defined only
+ if a <a href="http://tools.ietf.org/html/rfc3986#section-5.1">base <acronym title="Internationalized Resource Identifier">IRI</acronym>
+ can be established</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>].</p>
+
+ <p><strong><acronym title="Internationalized Resource Identifier">IRI</acronym> normalization:</strong>
+ Interoperability problems can be avoided by minting
+ only IRIs that are normalized according to
+ <a href="http://tools.ietf.org/html/rfc3987#section-5">Section 5</a>
+ of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. Non-normalized forms that are best avoided
+ include:</p>
+
+ <ul>
+ <li>Uppercase characters in scheme names and domain names</li>
+ <li>Percent-encoding of characters where it is not
+ required by <acronym title="Internationalized Resource Identifier">IRI</acronym> syntax</li>
+ <li>Explicitly stated HTTP default port
+ (<code>http://example.com:80/</code>);
+ <code>http://example.com/</code> is preferrable</li>
+ <li>Completely empty path in HTTP IRIs
+ (<code>http://example.com</code>);
+ <code>http://example.com/</code> is preferrable</li>
+ <li>“<code>/./</code>” or “<code>/../</code>” in the path
+ component of an <acronym title="Internationalized Resource Identifier">IRI</acronym></li>
+ <li>Lowercase hexadecimal letters within percent-encoding
+ triplets (“<code>%3F</code>” is preferable over
+ “<code>%3f</code>”)</li>
+ <li>Punycode-encoding of Internationalized Domain Names
+ in IRIs</li>
+ <li>IRIs that are not in Unicode Normalization
+ Form C [<cite><a class="bibref" rel="biblioentry" href="#bib-NFC">NFC</a></cite>]</li>
+ </ul>
+ </div>
+</div>
+
+
+<div id="section-Graph-Literal" typeof="bibo:Chapter" resource="#section-Graph-Literal" rel="bibo:chapter" class="section">
+ <h3><span class="secno">3.3 </span>Literals</h3>
+
+ <p>Literals are used to denote values such as strings, numbers and dates
+ by means of a lexical representation.</p>
+
+ <p>A <dfn id="dfn-literal">literal</dfn> in an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> consists of two or three
+ elements:</p>
+
+ <ul>
+ <li>a <dfn id="dfn-lexical-form">lexical form</dfn>, being a Unicode [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] string,
+ which <em class="rfc2119" title="should">should</em> be in Normal Form C [<cite><a class="bibref" rel="biblioentry" href="#bib-NFC">NFC</a></cite>],</li>
+ <li>a <dfn id="dfn-datatype-iri">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>, being an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> that determines
+ how the lexical form maps to a <a href="#dfn-literal-value" class="internalDFN">literal value</a>.</li>
+ </ul>
+
+ <p>A literal is a <dfn id="dfn-language-tagged-string">language-tagged string</dfn> if and only if its
+ <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a> is
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#langString</code>,
+ and only in this case the third element is present:</p>
+
+ <ul>
+ <li>a non-empty <dfn id="dfn-language-tag">language tag</dfn> as defined by [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>].
+ The language tag <em class="rfc2119" title="must">must</em> be well-formed according to
+ <a href="http://tools.ietf.org/html/bcp47#section-2.2.9">section 2.2.9</a>
+ of [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>], and <em class="rfc2119" title="must">must</em> be normalized to lowercase.</li>
+ </ul>
+
+ <p>Concrete syntaxes <em class="rfc2119" title="may">may</em> support <dfn title="simple literal" id="dfn-simple-literal">simple
+ literals</dfn>, consisting of only a <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>
+ without any datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> or language tag. Simple literals only
+ exist in concrete syntaxes, and are treated as
+ syntactic sugar for abstract syntax
+ <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> with the <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a>
+ <code>http://www.w3.org/2001/XMLSchema#string</code>.</p>
+
+ <p><dfn id="dfn-literal-equality">Literal equality</dfn>:
+ Two literals are equal if and only if the two
+ <a title="lexical form" href="#dfn-lexical-form" class="internalDFN">lexical forms</a>, the two
+ <a title="datatype IRI" href="#dfn-datatype-iri" class="internalDFN">datatype IRIs</a>, and the two
+ <a title="language tag" href="#dfn-language-tag" class="internalDFN">language tags</a> (if any)
+ compare equal, character by character.</p>
+</div>
+
+
+<div id="section-blank-nodes" typeof="bibo:Chapter" resource="#section-blank-nodes" rel="bibo:chapter" class="section">
+ <h3><span class="secno">3.4 </span>Blank Nodes</h3>
+
+ <p class="issue">Various proposals have been made for revising
+ this section, ranging from editorial re-wordings to major re-writes
+ that introduce notions of a “scope” for blank node identifiers
+ and define the concept of a “fresh” blank node. This is
+ <a href="https://www.w3.org/2011/rdf-wg/track/issues/107">ISSUE-107</a>.</p>
+
+ <p>The <dfn title="blank node" id="dfn-blank-node">blank nodes</dfn> in an RDF graph
+ are drawn from an infinite set. This set is disjoint from the set
+ of all <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and the set of all
+ <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>.
+ Otherwise, this set of blank nodes is arbitrary.</p>
+
+ <p>Given two blank nodes, it is
+ possible to determine whether or not they are the same.
+ Besides that, RDF makes no reference to any internal structure
+ of blank nodes.</p>
+
+ <p class="note" id="note-bnode-id">
+ <dfn title="blank node identifier" id="dfn-blank-node-identifier">Blank node identifiers</dfn>
+ are local identifiers that are used in some
+ <a title="concrete RDF syntax" href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntaxes</a>
+ or RDF store implementations.
+ They are always locally scoped to the file or RDF store,
+ and are <em>not</em> persistent or portable identifiers
+ for blank nodes. Blank node identifiers are <em>not</em>
+ part of the RDF abstract syntax, but are entirely dependent
+ on the concrete syntax or implementation. The syntactic restrictions
+ on blank node identifiers, if any, therefore also depend on
+ the concrete RDF syntax or implementation.</p>
+</div>
+
+
+<div id="section-skolemization" typeof="bibo:Chapter" resource="#section-skolemization" rel="bibo:chapter" class="section">
+ <h3><span class="secno">3.5 </span>Replacing Blank Nodes with IRIs</h3>
+
+ <p>Blank nodes do not have identifiers in the RDF abstract syntax. The
+ <a title="blank node identifier" href="#dfn-blank-node-identifier" class="internalDFN">blank node identifiers</a> introduced
+ by some concrete syntaxes have only
+ local scope and are purely an artifact of the serialization.</p>
+
+ <p>In situations where stronger identification is needed, systems <em class="rfc2119" title="may">may</em>
+ systematically replace some or all of the blank nodes in an RDF graph
+ with <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>. Systems wishing to do this <em class="rfc2119" title="should">should</em>
+ <a title="minting" href="#dfn-minting" class="internalDFN">mint</a> a new, globally
+ unique <acronym title="Internationalized Resource Identifier">IRI</acronym> (a <dfn id="dfn-skolem-iri">Skolem <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>) for each blank node so replaced.</p>
+
+ <p>This transformation does not appreciably change the meaning of an
+ RDF graph, provided that the Skolem IRIs do not occur anywhere else.
+ It does however permit the possibility of other graphs
+ subsequently using the Skolem IRIs, which is not possible
+ for blank nodes.</p>
+
+ <p>Systems may wish to mint Skolem IRIs in such a way that they can
+ recognize the IRIs as having been introduced solely to replace a blank
+ node. This allows the system to map IRIs back to the source blank node
+ if needed.</p>
+
+ <p>Systems that want Skolem IRIs to be recognizable outside of the system
+ boundaries <em class="rfc2119" title="should">should</em> use a well-known <acronym title="Internationalized Resource Identifier">IRI</acronym> [<cite><a class="bibref" rel="biblioentry" href="#bib-WELL-KNOWN">WELL-KNOWN</a></cite>] with the registered
+ name <code>genid</code>. This is an <acronym title="Internationalized Resource Identifier">IRI</acronym> that uses the HTTP or HTTPS scheme,
+ or another scheme that has been specified to use well-known IRIs; and whose
+ path component starts with <code>/.well-known/genid/</code>.
+
+ </p><p>For example, the authority responsible for the domain
+ <code>example.com</code> could mint the following recognizable Skolem <acronym title="Internationalized Resource Identifier">IRI</acronym>:</p>
+
+ <pre>http://example.com/.well-known/genid/d26a2d0e98334696f4ad70a677abc1f6</pre>
+
+ <p class="note">RFC 5785 [<cite><a class="bibref" rel="biblioentry" href="#bib-WELL-KNOWN">WELL-KNOWN</a></cite>] only specifies well-known URIs,
+ not IRIs. For the purpose of this document, a well-known <acronym title="Internationalized Resource Identifier">IRI</acronym> is any
+ <acronym title="Internationalized Resource Identifier">IRI</acronym> that results in a well-known <acronym title="Uniform Resource Identifier">URI</acronym> after <acronym title="Internationalized Resource Identifier">IRI</acronym>-to-<acronym title="Uniform Resource Identifier">URI</acronym> mapping [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>].</p>
+</div>
+
+
+<div id="graph-isomorphism" typeof="bibo:Chapter" resource="#graph-isomorphism" rel="bibo:chapter" class="section">
+ <h3><span class="secno">3.6 </span>Graph Isomorphism</h3>
+
+ <p id="section-graph-equality">Two
+ <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> <var>G</var> and <var>G'</var> are
+ <dfn title="graph isomorphism" id="dfn-graph-isomorphism">isomorphic</dfn> if there
+ is a bijection <var>M</var> between the sets of nodes of the two graphs,
+ such that:</p>
+
+ <ol>
+ <li><var>M</var> maps blank nodes to blank nodes.</li>
+ <li><var>M(lit)=lit</var> for all <a title="literal" href="#dfn-literal" class="internalDFN">RDF literals</a> <var>lit</var> which
+ are nodes of <var>G</var>.</li>
+
+ <li><var>M(uri)=uri</var> for all <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> <var>uri</var>
+ which are nodes of <var>G</var>.</li>
+
+ <li>The triple <var>( s, p, o )</var> is in <var>G</var> if and
+ only if the triple <var>( M(s), p, M(o) )</var> is in
+ <var>G'</var></li>
+ </ol>
+
+ <p>See also: <a href="#dfn-iri-equality" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym> equality</a>, <a href="#dfn-literal-equality" class="internalDFN">literal equality</a>.</p>
+
+ <p>With this definition, <var>M</var> shows how each blank node
+ in <var>G</var> can be replaced with
+ a new blank node to give <var>G'</var>. Graph isomorphism
+ is needed to support the RDF Test Cases [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-TESTCASES">RDF-TESTCASES</a></cite>] specification.</p>
+</div>
+
+</div>
+
+
+<div id="section-dataset" typeof="bibo:Chapter" resource="#section-dataset" rel="bibo:chapter" class="section">
+ <h2><span class="secno">4 </span>RDF Datasets</h2>
+
+ <p>An <dfn id="dfn-rdf-dataset">RDF Dataset</dfn> is a collection of
+ <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>, and comprises:</p>
+
+ <ul>
+ <li>Exactly one <dfn id="dfn-default-graph">default graph</dfn>, being an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>.
+ The default graph does not have a name and <em class="rfc2119" title="may">may</em> be empty.</li>
+ <li>Zero or more <dfn title="named graph" id="dfn-named-graph">named graphs</dfn>.
+ Each named graph is a pair consisting of an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>
+ (the <dfn id="dfn-graph-name">graph name</dfn>), and an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>.
+ Graph names are unique within an RDF dataset.</li>
+ </ul>
+
+ <p><a title="blank node" href="#dfn-blank-node" class="internalDFN">Blank nodes</a> <em class="rfc2119" title="may">may</em> be shared between graphs
+ in an <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>.</p>
+
+ <div class="note" id="note-datasets">
+ <p>Despite the use of the word “name”
+ in “<a href="#dfn-named-graph" class="internalDFN">named graph</a>”, the <a href="#dfn-graph-name" class="internalDFN">graph name</a> does not formally
+ <a href="#dfn-denote" class="internalDFN">denote</a> the graph. It is merely syntactically paired with
+ the graph. RDF does not place any formal restrictions on what
+ <a href="#dfn-resource" class="internalDFN">resource</a> the graph name may denote, nor on the relationship between
+ that resource and the graph.</p>
+
+ <p>Some <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>
+ implementations do not track empty <a title="named graph" href="#dfn-named-graph" class="internalDFN">named graphs</a>.
+ Applications can avoid interoperability issues by not
+ ascribing importance to the presence or absence of empty named graphs.</p>
+ </div>
+
+ <p class="issue">Should RDF Concepts define any operations on RDF datasets,
+ such as merge, union, isomorphism, equality, equivalence? Is anything
+ needed to support the TriG test cases, SPARQL, etc.? This is
+ <a href="https://www.w3.org/2011/rdf-wg/track/issues/111">ISSUE-111</a>.</p>
+</div>
+
+
+<div id="section-Datatypes" typeof="bibo:Chapter" resource="#section-Datatypes" rel="bibo:chapter" class="section">
+ <h2><span class="secno">5 </span>Datatypes</h2>
+
+ <p>Datatypes are used with RDF <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>
+ to represent values such as strings, numbers and dates.
+ The datatype abstraction used in RDF is compatible with XML Schema
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>]. Any datatype definition that conforms
+ to this abstraction <em class="rfc2119" title="may">may</em> be used in RDF, even if not defined
+ in terms of XML Schema. RDF re-uses many of the XML Schema
+ built-in datatypes,
+ and provides two additional built-in datatypes,
+ <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code> and <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code>.
+ The list of datatypes supported by an implementation is determined
+ by its <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>.</p>
+
+ <p>A <dfn id="dfn-datatype">datatype</dfn> consists of a <a href="#dfn-lexical-space" class="internalDFN">lexical space</a>,
+ a <a href="#dfn-value-space" class="internalDFN">value space</a> and a <a href="#dfn-lexical-to-value-mapping" class="internalDFN">lexical-to-value mapping</a>, and
+ is denoted by one or more <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>.</p>
+
+<p>The <dfn id="dfn-lexical-space">lexical space</dfn> of a datatype is a set of Unicode [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] strings.</p>
+
+ <p>The <dfn id="dfn-lexical-to-value-mapping">lexical-to-value mapping</dfn> of a datatype is a set of
+ pairs whose first element belongs to the <a href="#dfn-lexical-space" class="internalDFN">lexical space</a>,
+ and the second element belongs to the <dfn id="dfn-value-space">value space</dfn>
+ of the datatype. Each member of the lexical space is paired with exactly
+ one value, and is a <em>lexical representation</em>
+ of that value. The mapping can be seen as a function
+ from the lexical space to the value space.</p>
+
+ <p class="note"><a title="language-tagged string" href="#dfn-language-tagged-string" class="internalDFN">Language-tagged
+ strings</a> have the <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#langString</code>.
+ No datatype is formally defined for this <acronym title="Internationalized Resource Identifier">IRI</acronym> because the definition
+ of <a title="datatype" href="#dfn-datatype" class="internalDFN">datatypes</a> does not accommodate
+ <a title="language tag" href="#dfn-language-tag" class="internalDFN">language tags</a> in the <a href="#dfn-lexical-space" class="internalDFN">lexical space</a>.
+ The <a href="#dfn-value-space" class="internalDFN">value space</a> associated with this datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> is the set
+ of all pairs of strings and language tags.</p>
+
+ <p>For example, the XML Schema datatype <code>xsd:boolean</code>,
+ where each member of the <a href="#dfn-value-space" class="internalDFN">value space</a> has two lexical
+ representations, is defined as follows:</p>
+
+ <dl>
+ <dt>Lexical space:</dt>
+ <dd>{“<code>true</code>”, “<code>false</code>”, “<code>1</code>”, “<code>0</code>”}</dd>
+ <dt>Value space:</dt>
+ <dd>{<em><strong>true</strong></em>, <em><strong>false</strong></em>}</dd>
+ <dt>Lexical-to-value mapping</dt>
+ <dd>{
+ <“<code>true</code>”, <em><strong>true</strong></em>>,
+ <“<code>false</code>”, <em><strong>false</strong></em>>,
+ <“<code>1</code>”, <em><strong>true</strong></em>>,
+ <“<code>0</code>”, <em><strong>false</strong></em>>,
+ }</dd>
+ </dl>
+
+ <p>The <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> that can be defined using this
+ datatype are:</p>
+
+ <table rules="all" summary="This table lists the literals of type xsd:boolean.">
+ <tbody><tr>
+ <th>Literal</th>
+ <th>Value</th>
+ </tr>
+ <tr>
+ <td align="center"><“<code>true</code>”, <code>xsd:boolean</code>></td>
+ <td align="center"><em><strong>true</strong></em></td>
+ </tr>
+ <tr>
+ <td align="center"><“<code>false</code>”, <code>xsd:boolean</code>></td>
+ <td align="center"><em><strong>false</strong></em></td>
+ </tr>
+ <tr>
+ <td align="center"><“<code>1</code>”, <code>xsd:boolean</code>></td>
+ <td align="center"><em><strong>true</strong></em></td>
+ </tr>
+ <tr>
+ <td align="center"><“<code>0</code>”, <code>xsd:boolean</code>></td>
+ <td align="center"><em><strong>false</strong></em></td>
+ </tr>
+ </tbody></table>
+
+
+<div id="xsd-datatypes" typeof="bibo:Chapter" resource="#xsd-datatypes" rel="bibo:chapter" class="section">
+ <h3><span class="secno">5.1 </span>The XML Schema Built-in Datatypes</h3>
+
+ <p><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> of the form
+ <code>http://www.w3.org/2001/XMLSchema#<em>xxx</em></code>,
+ where <code><em>xxx</em></code>
+ is the name of a datatype, denote the built-in datatypes defined in
+ <em><a href="http://www.w3.org/TR/xmlschema11-2/">XML Schema 1.1 Part 2:
+ Datatypes</a></em> [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>]. The XML Schema built-in types
+ listed in the following table are the
+ <dfn id="dfn-rdf-compatible-xsd-types">RDF-compatible XSD types</dfn>. Their use is <em class="rfc2119" title="recommended">recommended</em>.</p>
+
+ <table rules="all" summary="A list of the RDF-compatible XSD types, with short descriptions">
+ <tbody><tr><th></th><th>Datatype</th><th>Value space (informative)</th></tr>
+
+ <tr><th rowspan="4">Core types</th><td><a href="http://www.w3.org/TR/xmlschema11-2/#string"><code>xsd:string</code></a></td><td>Character strings</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#boolean"><code>xsd:boolean</code></a></td><td>true, false</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#decimal"><code>xsd:decimal</code></a></td><td>Arbitrary-precision decimal numbers</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#integer"><code>xsd:integer</code></a></td><td>Arbitrary-size integer numbers</td></tr>
+
+ <tr><th rowspan="2">IEEE floating-point<br />numbers</th>
+ <td><a href="http://www.w3.org/TR/xmlschema11-2/#double"><code>xsd:double</code></a></td><td>64-bit floating point numbers incl. ±Inf, ±0, NaN</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#float"><code>xsd:float</code></a></td><td>32-bit floating point numbers incl. ±Inf, ±0, NaN</td></tr>
+
+ <tr><th rowspan="4">Time and date</th>
+ <td><a href="http://www.w3.org/TR/xmlschema11-2/#date"><code>xsd:date</code></a></td><td>Dates (yyyy-mm-dd) with or without timezone</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#time"><code>xsd:time</code></a></td><td>Times (hh:mm:ss.sss…) with or without timezone</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#dateTime"><code>xsd:dateTime</code></a></td><td>Date and time with or without timezone</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#dateTimeStamp"><code>xsd:dateTimeStamp</code></a></td><td>Date and time with required timezone</td></tr>
+
+ <tr><th rowspan="8">Recurring and<br />partial dates</th>
+ <td><a href="http://www.w3.org/TR/xmlschema11-2/#gYear"><code>xsd:gYear</code></a></td><td>Gregorian calendar year</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gMonth"><code>xsd:gMonth</code></a></td><td>Gregorian calendar month</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gDay"><code>xsd:gDay</code></a></td><td>Gregorian calendar day of the month</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gYearMonth"><code>xsd:gYearMonth</code></a></td><td>Gregorian calendar year and month</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gMonthDay"><code>xsd:gMonthDay</code></a></td><td>Gregorian calendar month and day</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#duration"><code>xsd:duration</code></a></td><td>Duration of time</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#yearMonthDuration"><code>xsd:yearMonthDuration</code></a></td><td>Duration of time (months and years only)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#dayTimeDuration"><code>xsd:dayTimeDuration</code></a></td><td>Duration of time (days, hours, minutes, seconds only)</td></tr>
+
+ <tr><th rowspan="12">Limited-range<br />integer numbers</th>
+ <td><a href="http://www.w3.org/TR/xmlschema11-2/#byte"><code>xsd:byte</code></a></td><td>-128…+127 (8 bit)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#short"><code>xsd:short</code></a></td><td>-32768…+32767 (16 bit)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#int"><code>xsd:int</code></a></td><td>-2147483648…+2147483647 (32 bit)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#long"><code>xsd:long</code></a></td><td>-9223372036854775808…+9223372036854775807 (64 bit)</td></tr>
+
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedByte"><code>xsd:unsignedByte</code></a></td><td>0…255 (8 bit)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedShort"><code>xsd:unsignedShort</code></a></td><td>0…65535 (16 bit)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedInt"><code>xsd:unsignedInt</code></a></td><td>0…4294967295 (32 bit)</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedLong"><code>xsd:unsignedLong</code></a></td><td>0…18446744073709551615 (64 bit)</td></tr>
+
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#positiveInteger"><code>xsd:positiveInteger</code></a></td><td>Integer numbers >0</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#nonNegativeInteger"><code>xsd:nonNegativeInteger</code></a></td><td>Integer numbers ≥0</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#negativeInteger"><code>xsd:negativeInteger</code></a></td><td>Integer numbers <0</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#nonPositiveInteger"><code>xsd:nonPositiveInteger</code></a></td><td>Integer numbers ≤0</td></tr>
+
+ <tr><th rowspan="2">Encoded binary data</th>
+ <td><a href="http://www.w3.org/TR/xmlschema11-2/#hexBinary"><code>xsd:hexBinary</code></a></td><td>Hex-encoded binary data</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#base64Binary"><code>xsd:base64Binary</code></a></td><td>Base64-encoded binary data</td></tr>
+
+ <tr><th rowspan="7">Miscellaneous<br />XSD types</th>
+ <td><a href="http://www.w3.org/TR/xmlschema11-2/#anyURI"><code>xsd:anyURI</code></a></td><td>Absolute or relative URIs and IRIs</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#language"><code>xsd:language</code></a></td><td>Language tags per [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>]</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#normalizedString"><code>xsd:normalizedString</code></a></td><td>Whitespace-normalized strings</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#token"><code>xsd:token</code></a></td><td>Tokenized strings</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#NMTOKEN"><code>xsd:NMTOKEN</code></a></td><td>XML NMTOKENs</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#Name"><code>xsd:Name</code></a></td><td>XML Names</td></tr>
+ <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#NCName"><code>xsd:NCName</code></a></td><td>XML NCNames</td></tr>
+ </tbody></table>
+
+ <p>The other built-in XML Schema datatypes are unsuitable
+ for various reasons, and <em class="rfc2119" title="should not">should not</em> be used.</p>
+
+ <div class="note">
+ <ul>
+ <li><a href="http://www.w3.org/TR/xmlschema11-2/#QName"><code>xsd:QName</code></a>
+ and
+ <a href="http://www.w3.org/TR/xmlschema11-2/#ENTITY"><code>xsd:ENTITY</code></a>
+ require an enclosing XML document context.</li>
+ <li><a href="http://www.w3.org/TR/xmlschema11-2/#ID"><code>xsd:ID</code></a>
+ and
+ <a href="http://www.w3.org/TR/xmlschema11-2/#IDREF"><code>xsd:IDREF</code></a>
+ are for cross references within an XML document.</li>
+ <li><a href="http://www.w3.org/TR/xmlschema11-2/#NOTATION"><code>xsd:NOTATION</code></a>
+ is not intended for direct use.</li>
+ <li><a href="http://www.w3.org/TR/xmlschema11-2/#IDREFS"><code>xsd:IDREFS</code></a>,
+ <a href="http://www.w3.org/TR/xmlschema11-2/#ENTITIES"><code>xsd:ENTITIES</code></a>
+ and
+ <a href="http://www.w3.org/TR/xmlschema11-2/#NMTOKENS"><code>xsd:NMTOKENS</code></a>
+ are sequence-valued datatypes which do not fit the RDF <a href="#dfn-datatype" class="internalDFN">datatype</a>
+ model.</li>
+ </ul>
+ </div>
+
+</div>
+
+
+<div id="section-html" typeof="bibo:Chapter" resource="#section-html" rel="bibo:chapter" class="section">
+ <h3><span class="secno">5.2 </span>The <code>rdf:HTML</code> Datatype</h3>
+
+ <p>RDF provides for HTML content as a possible <a href="#dfn-literal-value" class="internalDFN">literal value</a>.
+ This allows markup in literal values. Such content is indicated
+ in an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> using a <a href="#dfn-literal" class="internalDFN">literal</a> whose <a href="#dfn-datatype" class="internalDFN">datatype</a>
+ is a special built-in datatype <code><dfn id="dfn-rdf-html">rdf:HTML</dfn></code>.
+ This datatype is defined as follows:</p>
+
+ <dl>
+ <dt>An <acronym title="Internationalized Resource Identifier">IRI</acronym> denoting this datatype</dt>
+ <dd>is <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#HTML</code>.</dd>
+
+ <dt>The lexical space</dt>
+ <dd>is the set of Unicode [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] strings.</dd>
+
+ <dt>The value space</dt>
+ <dd>is a set of DOM
+ <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
+ nodes [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>]. Two
+ <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
+ nodes <em>A</em> and <em>B</em> are considered equal if and only if
+ the DOM method
+ <code><em>A</em>.<a href="http://www.w3.org/TR/dom/#dom-node-isequalnode">isEqualNode</a>(<em>B</em>)</code>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>] returns <code>true</code>.</dd>
+
+ <dt>The lexical-to-value mapping</dt>
+ <dd>
+ <p>Each member of the lexical space is associated with the result
+ of applying the following algorithm:</p>
+ <ul>
+ <li>Let <code>domnodes</code> be the list of
+ <a href="http://www.w3.org/TR/dom/#node">DOM nodes</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>]
+ that result from applying the
+ <a href="http://www.w3.org/TR/html5/the-end.html#parsing-html-fragments">HTML fragment parsing algorithm</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-HTML5">HTML5</a></cite>]
+ to the input string, without a context element.</li>
+ <li>Let <code>domfrag</code> be a DOM
+ <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>] whose <code>childNodes</code> attribute is equal to
+ <code>domnodes</code></li>
+ <li>Return <code>domfrag.<a href="http://www.w3.org/TR/dom/#dom-node-normalize">normalize</a>()</code></li>
+ </ul>
+ </dd>
+ </dl>
+
+ <p class="note" id="note-html">
+ Any language annotation (<code>lang="…"</code>) or
+ XML namespaces (<code>xmlns</code>) desired in the HTML content
+ must be included explicitly in the HTML literal. Relative URLs
+ in attributes such as <code>href</code> do not have a well-defined
+ base URL and are best avoided.
+ RDF applications may use additional equivalence relations,
+ such as that which relates an <code>xsd:string</code> with an
+ <code>rdf:HTML</code> literal corresponding to a single text node
+ of the same string.</p>
+</div>
+
+<div id="section-XMLLiteral" typeof="bibo:Chapter" resource="#section-XMLLiteral" rel="bibo:chapter" class="section">
+ <h3><span class="secno">5.3 </span>The <code>rdf:XMLLiteral</code> Datatype</h3>
+
+ <p>RDF provides for XML content as a possible <a href="#dfn-literal-value" class="internalDFN">literal value</a>.
+ Such content is indicated in an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> using a <a href="#dfn-literal" class="internalDFN">literal</a>
+ whose <a href="#dfn-datatype" class="internalDFN">datatype</a> is a special built-in datatype
+ <code><dfn id="dfn-rdf-xmlliteral">rdf:XMLLiteral</dfn></code>, which is defined as follows:</p>
+
+ <dl>
+ <dt id="XMLLiteral-uri">An <acronym title="Internationalized Resource Identifier">IRI</acronym> denoting
+ this datatype</dt>
+
+ <dd>is
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>.</dd>
+
+ <dt id="XMLLiteral-lexical-space">The lexical space</dt>
+
+ <dd>is the set of all strings which are well-balanced, self-contained
+ <a href="http://www.w3.org/TR/2000/REC-xml-20001006#NT-content">XML content</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-XML10">XML10</a></cite>]; and for which embedding between an arbitrary
+ XML start tag and an end tag yields a document conforming to
+ <a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/">XML Namespaces</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-NAMES">XML-NAMES</a></cite>].</dd>
+
+ <dt id="XMLLiteral-value-space">The value space</dt>
+
+ <dd>is a set of DOM
+ <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
+ nodes [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>]. Two
+ <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
+ nodes <em>A</em> and <em>B</em> are considered equal
+ if and only if the DOM method
+ <code><em>A</em>.<a href="http://www.w3.org/TR/dom/#dom-node-isequalnode">isEqualNode</a>(<em>B</em>)</code>
+ returns <code>true</code>.</dd>
+
+ <dt id="XMLLiteral-mapping">The lexical-to-value mapping</dt>
+
+ <dd>
+ <p>Each member of the lexical space is associated with the result
+ of applying the following algorithm:</p>
+ <ul>
+ <li>Let <code>domfrag</code> be a DOM
+ <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
+ node [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>] corresponding to the input string</li>
+ <li>Return <code>domfrag.<a href="http://www.w3.org/TR/dom/#dom-node-normalize">normalize</a>()</code></li>
+ </ul></dd>
+
+ <dt id="XMLLiteral-canonical">The canonical mapping</dt>
+ <dd>defines a
+ <a href="http://www.w3.org/TR/xmlschema11-2/#dt-canonical-mapping">canonical lexical form</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>] for each member of the value space.
+ The <code>rdf:XMLLiteral</code> canonical mapping is the
+ <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/#def-exclusive-XML-canonicalization-method">exclusive
+ XML canonicalization method</a> (<em>with comments, with empty
+ <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/#def-InclusiveNamespaces-PrefixList">
+ InclusiveNamespaces PrefixList</a></em>) [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-EXC-C14N">XML-EXC-C14N</a></cite>].
+
+ </dd></dl>
+
+ <p class="note">Any XML namespace declarations (<code>xmlns</code>),
+ language annotation (<code>xml:lang</code>) or base <acronym title="Uniform Resource Identifier">URI</acronym>
+ declarations (<code>xml:base</code>) desired in the
+ XML content must be included explicitly in the XML literal.
+ Note that some concrete RDF syntaxes may define mechanisms
+ for inheriting them from the context
+ (e.g., <a href="http://www.w3.org/TR/rdf-syntax-grammar/#parseTypeLiteralPropertyElt"><code>@parseType="literal"</code></a>
+ in RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>]).</p>
+</div>
+
+<div id="datatype-maps" typeof="bibo:Chapter" resource="#datatype-maps" rel="bibo:chapter" class="section">
+ <h3><span class="secno">5.4 </span>Datatype Maps</h3>
+
+ <p>A <dfn id="dfn-datatype-map">datatype map</dfn> is an implementation-defined set of
+ <<a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>, <a href="#dfn-datatype" class="internalDFN">datatype</a>> pairs such that no
+ <acronym title="Internationalized Resource Identifier">IRI</acronym> appears twice in the set.
+ It can be seen as a function from IRIs to datatypes,
+ where the IRIs denote the datatypes.</p>
+
+ <p>If a <a href="#dfn-datatype-map" class="internalDFN">datatype map</a> contains the <acronym title="Internationalized Resource Identifier">IRI</acronym>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>,
+ then it <em class="rfc2119" title="must">must</em> be paired with the datatype
+ <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code>.</p>
+
+ <p>If a <a href="#dfn-datatype-map" class="internalDFN">datatype map</a> contains the <acronym title="Internationalized Resource Identifier">IRI</acronym>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#HTML</code>,
+ then it <em class="rfc2119" title="must">must</em> be paired with the datatype
+ <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code>.</p>
+
+ <p>If a <a href="#dfn-datatype-map" class="internalDFN">datatype map</a> contains an <acronym title="Internationalized Resource Identifier">IRI</acronym> of the form
+ <code>http://www.w3.org/2001/XMLSchema#<em>xxx</em></code>,
+ then it <em class="rfc2119" title="must">must</em> be paired with the
+ <a title="RDF-compatible XSD types" href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD type</a>
+ named <code>xsd:<em>xxx</em></code>.</p><p>
+
+ </p><p>Other specifications
+ <em class="rfc2119" title="may">may</em> impose additional constraints on the <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>,
+ for example, require support for certain datatypes.</p>
+
+ <p class="note" id="note-custom-datatypes">The Web Ontology Language
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>] offers facilities for formally defining
+ <a href="http://www.w3.org/TR/owl2-syntax/#Datatype_Definitions">custom
+ datatypes</a> that can be used with RDF. Furthermore, a practice for
+ identifying
+ <a href="http://www.w3.org/TR/swbp-xsch-datatypes/#sec-userDefined">
+ user-defined simple XML Schema datatypes</a>
+ is suggested in [<cite><a class="bibref" rel="biblioentry" href="#bib-SWBP-XSCH-DATATYPES">SWBP-XSCH-DATATYPES</a></cite>]. RDF implementations
+ are not required to support either of these facilities.</p>
+</div>
+
+
+<div id="section-Literal-Value" typeof="bibo:Chapter" resource="#section-Literal-Value" rel="bibo:chapter" class="section">
+ <h3><span class="secno">5.5 </span>The Value Corresponding to a Literal</h3>
+
+ <p>The <dfn id="dfn-literal-value">literal value</dfn> associated with a <a href="#dfn-literal" class="internalDFN">literal</a> is:</p>
+
+ <ol>
+ <li><strong>If the literal is a <a href="#dfn-language-tagged-string" class="internalDFN">language-tagged string</a>,</strong>
+ then the literal value is a pair consisting of its <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>
+ and its <a href="#dfn-language-tag" class="internalDFN">language tag</a>, in that order.</li>
+ <li><strong>If the literal's <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a> is not in the
+ implementation-defined <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>,</strong> then the literal value
+ is not defined by this specification.</li>
+ <li>Let <em>d</em> be the <a href="#dfn-datatype" class="internalDFN">datatype</a> associated with the
+ datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> in the implementation-defined datatype map.</li>
+ <li><strong>If the literal's <a href="#dfn-lexical-form" class="internalDFN">lexical form</a> is in the
+ <a href="#dfn-lexical-space" class="internalDFN">lexical space</a> of <em>d</em>,</strong> then the literal value
+ is the result of applying the <a href="#dfn-lexical-to-value-mapping" class="internalDFN">lexical-to-value mapping</a>
+ of <em>d</em> to the <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>.</li>
+ <li><strong>Otherwise,</strong> the literal is
+ <dfn id="dfn-ill-typed">ill-typed</dfn>, and no literal value can be
+ associated with the literal. Such a case, while in error, is not
+ <em>syntactically</em> ill-formed.</li>
+ </ol>
+
+ <p class="issue">What does it mean when a literal is ill-typed or when something is not in the datatype map? What should an implementation do? Should authors avoid generating such graphs? Should consumers reject it? Is an implementation that rejects ill-formed xsd:dates conforming? Why is an ill-typed literal not necessarily an inconsistency? This is <a href="https://www.w3.org/2011/rdf-wg/track/issues/109">ISSUE-109</a>.</p>
+</div>
+
+
+</div>
+
+
+<div id="section-fragID" class="informative section" typeof="bibo:Chapter" resource="#section-fragID" rel="bibo:chapter">
+ <h2><span class="secno">6 </span>Fragment Identifiers</h2><p><em>This section is non-normative.</em></p>
+
+ <p class="issue">This section addresses the use of fragment IRIs
+ in concrete syntaxes for <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>, but not
+ for <a title="RDF dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a>. Going beyond the questions
+ of pure fragment identifiers, the introduction of RDF datasets raises
+ additional questions related to content negotiation and the
+ authoritativeness of representations. For example, is it legitimate
+ to content-negotiate between an RDF graph representation and an
+ RDF dataset representation that only contains a default graph?
+ Are the contents of graphs named <code><#xxx></code> an
+ authoritative representation of whatever is identified by
+ <code><#xxx></code>? This is
+ <a href="https://www.w3.org/2011/rdf-wg/track/issues/105">ISSUE-105</a>.</p>
+
+ <p>RDF uses <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, which may include
+ <dfn id="dfn-fragment-identifiers">fragment identifiers</dfn>, as resource identifiers.
+ The semantics of fragment identifiers is
+ <a href="http://tools.ietf.org/html/rfc3986#section-3.5">defined in
+ RFC 3986</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>]: They identify a secondary resource
+ that is usually a part of, view of, defined in, or described in
+ the primary resource, and the precise semantics depend on the set
+ of representations that might result from a retrieval action
+ on the primary resource.</p>
+
+ <p>This section discusses the handling of fragment identifiers
+ in representations that encode <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>.</p>
+
+ <p>In RDF-bearing representations of a primary resource
+ <code><foo></code>,
+ the secondary resource identified by a fragment <code>bar</code>
+ is the <a href="#dfn-resource" class="internalDFN">resource</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by the
+ full <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> <code><foo#bar></code> in the <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>.
+ Since IRIs in RDF graphs can denote anything, this can be
+ something external to the representation, or even external
+ to the web.</p>
+
+ <p>In this way, the RDF-bearing representation acts as an intermediary
+ between the web-accessible primary resource, and some set of possibly
+ non-web or abstract entities that the <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> may describe.</p>
+
+ <p>In cases where other specifications constrain the semantics of
+ fragment identifiers in RDF-bearing representations, the encoded
+ <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> should use fragment identifiers in a way that is consistent
+ with these constraints. For example, in an HTML+RDFa document [<cite><a class="bibref" rel="biblioentry" href="#bib-HTML-RDFA">HTML-RDFA</a></cite>],
+ the fragment <code>chapter1</code> may identify a document section
+ via the semantics of HTML's <code>@name</code> or <code>@id</code>
+ attributes. The <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> <code><#chapter1></code> should
+ then be taken to <a href="#dfn-denote" class="internalDFN">denote</a> that same section in any RDFa-encoded
+ <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a> within the same document.
+ Similarly, if the <code>@xml:id</code> attribute [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-ID">XML-ID</a></cite>] is used
+ in an RDF/XML document, then the corresponding <acronym title="Internationalized Resource Identifier">IRI</acronym>
+ should be taken to denote an XML element.</p>
+
+ <p>Primary resources may have multiple representations that are
+ made available via
+ <a href="http://www.w3.org/TR/webarch/#frag-coneg">content negotiation</a>
+ [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>]. Fragments in RDF-bearing representations
+ should be used in a way that is consistent with the semantics imposed by any
+ non-RDF representations. For example, if the fragment
+ <code>chapter1</code> identifies a document section in an
+ HTML representation of the primary resource, then the <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>
+ <code><#chapter1></code>
+ should be taken to <a href="#dfn-denote" class="internalDFN">denote</a> that same section in all RDF-bearing
+ representations of the same primary resource.</p>
+</div>
+
+
+<div id="section-Acknowledgments" class="informative section" typeof="bibo:Chapter" resource="#section-Acknowledgments" rel="bibo:chapter">
+ <h2><span class="secno">7 </span>Acknowledgments</h2><p><em>This section is non-normative.</em></p>
+
+ <p>The RDF 1.1 editors acknowledge valuable contributions from
+ Thomas Baker, Dan Brickley, Gavin Carothers, Jeremy Carroll,
+ Pierre-Antoine Champin, Dan Connolly,
+ John Cowan, Martin J. Dürst, Alex Hall, Steve Harris, Pat Hayes,
+ Ivan Herman, Peter F. Patel-Schneider, Addison Phillips,
+ Eric Prud'hommeaux, Andy Seaborne, Leif Halvard Silli,
+ Nathan Rixham, Dominik Tomaszuk and Antoine Zimmermann.</p>
+
+ <p>The RDF 2004 editors acknowledge valuable contributions from
+ Frank Manola, Pat Hayes, Dan Brickley, Jos de Roo, Sergey Melnik,
+ Dave Beckett, Patrick Stickler, Peter F. Patel-Schneider, Jerome Euzenat,
+ Massimo Marchiori, Tim Berners-Lee, Dave Reynolds and Dan Connolly.</p>
+
+ <p>This specification is a product of extended deliberations by the
+ <a href="http://www.w3.org/2000/09/dbwg/details?group=46168&public=1">members of the RDF Working Group</a>.
+ It draws upon two earlier specifications,
+ <em><a href="http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/">RDF Model and Syntax</a></em>, edited by Ora Lassilla and Ralph Swick,
+ and <em><a href="http://www.w3.org/TR/2000/CR-rdf-schema-20000327/">RDF Schema</a></em>, edited by Dan Brickley and R. V. Guha, which were produced by
+ <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#section-Acknowledgments">members
+ of the RDFcore and Schema Working Groups</a>.</p>
+</div>
+
+
+<div class="appendix informative section" id="changes" typeof="bibo:Chapter" resource="#changes" rel="bibo:chapter">
+ <h2><span class="secno">A </span>Changes between RDF 2004 and RDF 1.1</h2><p><em>This section is non-normative.</em></p>
+
+ <p class="issue">The Working Group intends to publish a separate
+ Working Group Note entitled
+ <em>RDF 1.1 New Features and Migration Guide</em>. This is
+ <a href="http://www.w3.org/2011/rdf-wg/track/actions/193">ACTION-193</a>.
+ Some or all material in this section may be moved to that document. In the
+ meantime, the <a href="#change-log">Change Log</a> is a good indication
+ as to what else has changed and why.</p>
+
+ <p>This section discusses changes between the
+ <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/">2004
+ Recommendation of <em>RDF Concepts and Abstract Syntax</em></a> and
+ the RDF 1.1 versions of this specification.</p>
+
+ <p>Previous versions of RDF used the term
+ “<dfn id="dfn-rdf-uri-reference">RDF <acronym title="Uniform Resource Identifier">URI</acronym> Reference</dfn>” instead of “<acronym title="Internationalized Resource Identifier">IRI</acronym>” and allowed
+ additional characters:
+ “<code><</code>”, “<code>></code>”,
+ “<code>{</code>”, “<code>}</code>”,
+ “<code>|</code>”, “<code>\</code>”,
+ “<code>^</code>”, “<code>`</code>”,
+ ‘<code>“</code>’ (double quote), and “<code> </code>” (space).
+ In IRIs, these characters must be percent-encoded as
+ described in <a href="http://tools.ietf.org/html/rfc3986#section-2.1">section 2.1</a>
+ of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>].</p>
+
+ <p>In earlier versions of RDF, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>
+ with a <a href="#dfn-language-tag" class="internalDFN">language tag</a> did not have a <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a>, and
+ <a title="simple literal" href="#dfn-simple-literal" class="internalDFN">simple literals</a> could appear
+ directly in the abstract syntax. Simple literals and literals with a
+ language tag were collectively known as
+ <dfn title="plain literal" id="dfn-plain-literal">plain literals</dfn>.</p>
+
+ <p>Earlier versions of RDF permitted
+ <a title="language tag" href="#dfn-language-tag" class="internalDFN">language tags</a> that
+ adhered to the generic tag/subtag syntax of language tags,
+ but were not well-formed according to [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>]. Such
+ language tags do not conform to RDF 1.1.</p>
+
+ <p>The <code>xsd:string</code> datatype does not
+ permit the <code>#x0</code> character, and implementations may not permit
+ control codes in the <code>#x1-#x1F</code> range. Earlier versions of
+ RDF allowed these characters in
+ <a title="simple literal" href="#dfn-simple-literal" class="internalDFN">simple literals</a>, although they
+ could never be serialized in a <acronym title="World Wide Web Consortium">W3C</acronym>-recommended concrete syntax.</p>
+</div>
+
+
+<div class="appendix informative section" id="change-log" typeof="bibo:Chapter" resource="#change-log" rel="bibo:chapter">
+ <h2><span class="secno">B </span>Change Log</h2><p><em>This section is non-normative.</em></p>
+
+
+<div class="appendix section" id="changes-wd3" typeof="bibo:Chapter" resource="#changes-wd3" rel="bibo:chapter">
+ <h3><span class="secno">B.1 </span>Changes from 05 June 2012 WD to this version</h3>
+
+ <p>This section lists changes from the
+ <a href="http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/">05 June 2012 Working Draft (WD)</a> to this Working Draft of
+ <em>RDF 1.1 Concepts and Abstract Syntax</em>.</p>
+
+ <ul>
+ <li>2013-01-14: Editorial changes in response to <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Nov/0354.html">reviews from Antoine Zimmermann</a> <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Nov/0360.html">and Peter Patel-Schneider</a></li>
+ <li>2012-11-21: Replaced the placeholder term “g-box” with “<a href="#dfn-rdf-source" class="internalDFN">RDF source</a>” (<a href="https://www.w3.org/2011/rdf-wg/track/issues/110">ISSUE-110</a>)</li>
+ <li>2012-11-21: Removed various Notes (as <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Nov/0131.html">listed here</a>), and refactored others (<a href="https://www.w3.org/2011/rdf-wg/track/issues/104">ISSUE-104</a>)</li>
+ <li>2012-11-17: Many changes to Introduction, including mostly new subsections on <a href="#managing-graphs">Working with Multiple RDF Graphs and G-Boxes</a>, <a href="#entailment">Equivalence, Entailment and Inconsistencies</a>, and <a href="#rdf-documents">RDF Documents and Syntaxes</a></li>
+ <li>2012-11-17: Reverted section on <a href="#section-blank-nodes">Blank Nodes</a> to earlier state</li>
+ <li>2012-11-17: Changes, mostly but not exclusively editorial, to section on <a href="#section-fragID">Fragment Identifiers</a></li>
+ <li>2012-11-13: Remove the notion of other specs conforming to this spec from the <a href="#conformance">Conformance</a> section. This spec simply provides definitions that other specs can use.</li>
+ <li>2012-11-09: Updated the <a href="#section-dataset">section on RDF datasets</a> to reflect <a href="http://www.w3.org/2011/rdf-wg/meeting/2012-10-29">various WG resolutions</a> around named graphs</li>
+ <li>2012-11-09: Re-wrote the <a href="#section-blank-nodes">section on Blank Nodes</a>, including a definition of “fresh blank nodes” and an extended Note on standardizing apart blank node IDs</li>
+ <li>2012-11-09: Moved all informative material about changes between RDF 2004 and RDF 1.1 to a <a href="#changes">new appendix</a></li>
+ <li>2012-11-07: Add <a href="#change-over-time">new informative section on Change Over Time</a></li>
+ <li>2012-11-07: New <a href="#abstract">abstract</a>, based on comments from Dan Connolly</li>
+ <li>2012-11-06: Tweak definition of <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> to avoid apparent contradiction (<a href="http://www.w3.org/2011/rdf-wg/track/issues/94">ISSUE-94</a>)</li>
+ <li>2012-11-06: Add a <a href="#note-custom-datatypes">note</a> on the use of OWL2 custom datatypes and simple user-defined XML Schema datatypes (<a href="http://www.w3.org/2011/rdf-wg/track/issues/96">ISSUE-96</a>)</li>
+ <li>2012-11-06: Add a <a href="#note-empty-named-graphs">note on empty named graphs</a> (<a href="http://www.w3.org/2011/rdf-wg/track/issues/22">ISSUE-22</a>)</li>
+ <li>2012-11-06: Modify the <a title="relative IRI" href="#dfn-relative-iri" class="internalDFN">Note on relative IRIs</a> to stress their usefulness and to clarify the role of RFC 3986 in the resolution process</li>
+ <li>2012-11-06: Informatively <a href="#referents">explain</a> that IRIs in this spec are treated only as nodes in a graph data model, and no interaction model is implied</li>
+ <li>2012-08-09: Clarify that all datatypes are optional, but RDF-conformant specifications <em class="rfc2119" title="may">may</em> require specific <a title="datatype map" href="#dfn-datatype-map" class="internalDFN">datatype maps</a></li>
+ </ul>
+</div>
+
+
+<div class="appendix section" id="changes-wd2" typeof="bibo:Chapter" resource="#changes-wd2" rel="bibo:chapter">
+ <h3><span class="secno">B.2 </span>Changes from FPWD to 05 June 2012 WD</h3>
+
+ <p>This section lists changes from the
+ <a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">First Public Working Draft (FPWD)</a>
+ to the <a href="http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/">05 June 2012 Working Draft (WD)</a> of
+ <em>RDF 1.1 Concepts and Abstract Syntax</em>.</p>
+
+ <ul>
+ <li>2012-05-31: Update <a href="#section-Acknowledgments">Acknowledgements</a> for RDF 1.1; added RDFa 1.1 markup</li>
+ <li>2012-05-24: Moved the multigraph section to an earlier position and renamed it to “<a href="#section-dataset">RDF Datasets</a>”</li>
+ <li>2012-05-17: Changed normative reference for DOM in <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code> from [DOM3CORE] to [DOM4] as we need DOM4 anyways for <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code></li>
+ <li>2012-05-17: Added <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code> datatype (<a href="http://www.w3.org/2011/rdf-wg/track/issues/63">ISSUE-63</a>)</li>
+ <li>2012-05-17: Added <a href="http://www.w3.org/TR/xmlschema11-2/#duration"><code>xsd:duration</code></a> to list of <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a> (<a href="http://www.w3.org/2011/rdf-wg/track/issues/88">ISSUE-88</a>)</li>
+ <li>2012-05-14: Replaced the example graph diagram in <a href="#data-model">Section 1.1</a> with a re-drawn SVG version, with support from Dominik Tomaszuk</li>
+ <li>2012-05-10: New <a href="#conformance">Conformance section</a> to explain that this specification is not implemented directly, but through other specifications that use our definitions</li>
+ <li>2012-05-10: Simplified <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code>'s new value space slightly after feedback from Ivan Herman and Arnaud Le Hors.</li>
+ <li>2012-05-10: Added an informative subsection on <a href="#vocabularies">RDF vocabularies and namespace IRIs</a>.</li>
+ <li>2012-05-09: Removed an example from the conformance section that didn't make sense any more with the modified <code>rdf:XMLLiteral</code>. Added some new issue boxes.</li>
+ <li>2012-05-09: <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code> no longer requires lexical forms to be canonicalized, and the value space is now defined in terms of [DOM-LEVEL-3-CORE] (<a href="https://www.w3.org/2011/rdf-wg/track/issues/13">ISSUE-13</a>)</li>
+ <li>2012-05-09: Removed Section 3 <em>RDF Vocabulary <acronym title="Internationalized Resource Identifier">IRI</acronym> and Namespace</em>; its contents will be folded into the RDF Schema document</li>
+ <li>2012-05-02: Renamed “graph equivalence” to “<a href="#dfn-graph-isomorphism" class="internalDFN">graph isomorphism</a>” (<a href="https://www.w3.org/2011/rdf-wg/track/issues/86">ISSUE-86</a>)</li>
+ <li>2012-05-02: Updated [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-1">XMLSCHEMA11-1</a></cite>] and [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>] references to the new REC versions</li>
+ <li>2012-05-02: Added the new XSD 1.1 datatypes <a href="http://www.w3.org/TR/xmlschema11-2/#dayTimeDuration">xsd:dayTimeDuration</a>, <a href="http://www.w3.org/TR/xmlschema11-2/#yearMonthDuration">xsd:yearMonthDuration</a> and <a href="http://www.w3.org/TR/xmlschema11-2/#dateTimeStamp">xsd:dateTimeStamp</a> to the list of <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a> (<a href="https://www.w3.org/2011/rdf-wg/track/issues/66">ISSUE-66</a>)</li>
+ <li>2012-04-26: Remove normative definition of “property” as it disagreed with RDF Semantics; small editorial changes.</li>
+ <li>2011-11-21: Updated XHTML 1.0 reference to XHTML 1.1</li>
+ <li>2011-11-20: Added table of <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a>, and definition of <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>, both adapted from previous content in [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>]
+ </li><li>2011-11-18: Replaced informative <em>Introduction</em> and <em>RDF Concepts</em> sections with a new extended introduction. Folded some content from <em>RDF Concepts</em> into the later normative sections, mostly as examples and notes.</li>
+ <li>2011-11-10: Changed XSD references to version 1.1</li>
+ <li>2011-11-10: Replaced the <a href="#section-fragID">section on fragment identifiers</a> with an updated account that follows RFC 3986</li>
+ <li>2011-11-09: Updated the two sections on literals to reflect the <a href="http://www.w3.org/2011/rdf-wg/track/issues/71">ISSUE-71</a> resolution that literals with language tag now have the datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> <code>rdf:langString</code>. Formally introduced the term “language-tagged string”.</li>
+ <li>2011-11-09: Add a note that explains that #x0-#x1F are no longer allowed in simple literals
+ </li></ul>
+</div>
+
+<div class="appendix section" id="changes-fpwd" typeof="bibo:Chapter" resource="#changes-fpwd" rel="bibo:chapter">
+ <h3><span class="secno">B.3 </span>Changes from RDF 2004 to FPWD</h3>
+
+ <p>This section lists changes from the
+ <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/">2004 Recommendation of
+ <em>RDF Concepts and Abstract Syntax</em></a> to the
+ <a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">First Public Working Draft (FPWD) of
+ <em>RDF 1.1 Concepts and Abstract Syntax</em></a>.</p>
+
+ <ul>
+ <li>2011-08-13: Updated Turtle reference to Turtle FPWD</li>
+ <li>2011-07-21: Condensed the 2004 acknowledgements</li>
+ <li>2011-07-21: Updated the two sections on literals to reflect the <a href="http://www.w3.org/2011/rdf-wg/track/issues/12">ISSUE-12</a> resolution that simple literals are no longer part of the abstract syntax. Formally introduced the terms “language-tagged literal”, “simple literal”.</li>
+ <li>2011-07-21: Updated the introduction, and removed many mentions of RDF/XML. Changed the normative reference for the terms in the RDF namespace from the RDF/XML spec to the RDF Schema spec. Removed any mention of the 1999 version of RDF.</li>
+ <li>2011-07-21: Replaced RFC 2279 reference (UTF-8) with RFC 3629</li>
+ <li>2011-07-20: Removed informative sections “Motivations and Goals” (see <a href="http://www.w3.org/TR/rdf-concepts/#section-Overview">RDF 2004 version</a>) and “RDF Expression of Simple Facts” (see <a href="http://www.w3.org/TR/rdf-concepts/#section-SimpleFacts">RDF 2004 version</a>)</li>
+ <li>2011-06-01: Replaced the <acronym title="Uniform Resource Identifier">URI</acronym> References section with <a href="#section-IRIs">new section on IRIs</a>, and changed “RDF <acronym title="Uniform Resource Identifier">URI</acronym> Reference” to “<acronym title="Internationalized Resource Identifier">IRI</acronym>” throughout the document.</li>
+ <li>2011-06-01: Changed language tag definition to require well-formedness according to BCP47; added a note that this invalidates some RDF</li>
+ <li>2011-05-25: Added boxes for known WG issues throught the document</li>
+ <li>2011-05-25: Deleted “Structure of this Document” section, it added no value beyond the TOC</li>
+ <li>2011-05-25: Implemented resolution of <a href="http://www.w3.org/2011/rdf-wg/track/issues/40">ISSUE-40: Skolemization advice in the RDF dcocument</a> by adding a section on <a href="#section-skolemization">Replacing Blank Nodes with IRIs</a></li>
+ <li>2011-05-25: rdf:XMLLiteral is disjoint from any datatype not explicitly related to it, per erratum <a href="http://www.w3.org/2001/sw/RDFCore/errata#concept-xmlliteral">[concept-xmlliteral]</a></li>
+ <li>2011-05-25: Added Conformance section with RFC2119 reference</li>
+ <li>2011-05-25: Updated all <acronym title="World Wide Web Consortium">W3C</acronym> references to latest editions, and Unicode from v3 to v4</li>
+ <li>2011-05-24: Converted to ReSpec, changed metadata to reflect RDF 1.1</li>
+ </ul>
+</div>
+
+</div>
+
+
+
+
+<div id="references" class="appendix section" typeof="bibo:Chapter" resource="#references" rel="bibo:chapter"><h2><span class="secno">C </span>References</h2><div id="normative-references" typeof="bibo:Chapter" resource="#normative-references" rel="bibo:chapter" class="section"><h3><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography" about=""><dt id="bib-BCP47">[BCP47]</dt><dd rel="dcterms:requires">A. Phillips; M. Davis. <a href="http://tools.ietf.org/html/bcp47"><cite>Tags for Identifying Languages</cite></a> September 2009. IETF Best Current Practice. URL: <a href="http://tools.ietf.org/html/bcp47">http://tools.ietf.org/html/bcp47</a>
+</dd><dt id="bib-DOM4">[DOM4]</dt><dd rel="dcterms:requires">Anne van Kesteren; Aryeh Gregor; Ms2ger. <a href="http://www.w3.org/TR/2012/WD-dom-20120405/"><cite>DOM4.</cite></a> 5 April 2012. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2012/WD-dom-20120405/">http://www.w3.org/TR/2012/WD-dom-20120405/</a>
+</dd><dt id="bib-HTML5">[HTML5]</dt><dd rel="dcterms:requires">Ian Hickson; David Hyatt. <a href="http://www.w3.org/TR/html5"><cite>HTML5.</cite></a> 25 October 2012. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2012/WD-html5-20121025/">http://www.w3.org/TR/2012/WD-html5-20121025/</a>
+</dd><dt id="bib-NFC">[NFC]</dt><dd rel="dcterms:requires">M. Davis, Ken Whistler. <a href="http://www.unicode.org/reports/tr15/"><cite>TR15, Unicode Normalization Forms.</cite></a>. 17 September 2010, URL: <a href="http://www.unicode.org/reports/tr15/">http://www.unicode.org/reports/tr15/</a>
+</dd><dt id="bib-RFC2119">[RFC2119]</dt><dd rel="dcterms:requires">S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate Requirement Levels.</cite></a> March 1997. Internet RFC 2119. URL: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
+</dd><dt id="bib-RFC3987">[RFC3987]</dt><dd rel="dcterms:requires">M. Dürst; M. Suignard. <a href="http://www.ietf.org/rfc/rfc3987.txt"><cite>Internationalized Resource Identifiers (IRIs).</cite></a> January 2005. Internet RFC 3987. URL: <a href="http://www.ietf.org/rfc/rfc3987.txt">http://www.ietf.org/rfc/rfc3987.txt</a>
+</dd><dt id="bib-UNICODE">[UNICODE]</dt><dd rel="dcterms:requires">The Unicode Consortium. <a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html"><cite>The Unicode Standard.</cite></a>. Defined by: The Unicode Standard, Version 6.2.0, (Mountain View, CA: The Unicode Consortium, 2012. ISBN 978-1-936213-07-8) , as updated from time to time by the publication of new versions URL: <a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html">http://www.unicode.org/unicode/standard/versions/enumeratedversions.html</a>
+</dd><dt id="bib-XML-EXC-C14N">[XML-EXC-C14N]</dt><dd rel="dcterms:requires">Donald E. Eastlake 3rd; Joseph Reagle; John Boyer. <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/"><cite>Exclusive XML Canonicalization Version 1.0.</cite></a> 18 July 2002. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/">http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/</a>
+</dd><dt id="bib-XML-NAMES">[XML-NAMES]</dt><dd rel="dcterms:requires">Richard Tobin; et al. <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/"><cite>Namespaces in XML 1.0 (Third Edition).</cite></a> 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</a>
+</dd><dt id="bib-XML10">[XML10]</dt><dd rel="dcterms:requires">C. M. Sperberg-McQueen; et al. <a href="http://www.w3.org/TR/2008/REC-xml-20081126/"><cite>Extensible Markup Language (XML) 1.0 (Fifth Edition).</cite></a> 26 November 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</a>
+</dd><dt id="bib-XMLSCHEMA11-2">[XMLSCHEMA11-2]</dt><dd rel="dcterms:requires">Henry S. Thompson; et al. <a href="http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/"><cite>W3C XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes.</cite></a> 5 April 2012. W3C Recommendation URL: <a href="http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/">http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/</a>
+</dd></dl></div><div id="informative-references" typeof="bibo:Chapter" resource="#informative-references" rel="bibo:chapter" class="section"><h3><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography" about=""><dt id="bib-COOLURIS">[COOLURIS]</dt><dd rel="dcterms:references">Richard Cyganiak; Leo Sauermann. <a href="http://www.w3.org/TR/2008/NOTE-cooluris-20081203"><cite>Cool URIs for the Semantic Web.</cite></a> 3 December 2008. W3C Note. URL: <a href="http://www.w3.org/TR/2008/NOTE-cooluris-20081203">http://www.w3.org/TR/2008/NOTE-cooluris-20081203</a>
+</dd><dt id="bib-HTML-RDFA">[HTML-RDFA]</dt><dd rel="dcterms:references">Manu Sporny; et al. <a href="http://www.w3.org/TR/2011/WD-rdfa-in-html-20110525/"><cite>HTML+RDFa 1.1</cite></a> 25 May 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2011/WD-rdfa-in-html-20110525/">http://www.w3.org/TR/2011/WD-rdfa-in-html-20110525/</a>
+</dd><dt id="bib-N-TRIPLES">[N-TRIPLES]</dt><dd rel="dcterms:references">Jan Grant; Dave Beckett. <a href="http://www.w3.org/TR/rdf-testcases/#ntriples"><cite>N-Triples</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-testcases/#ntriples">http://www.w3.org/TR/rdf-testcases/#ntriples</a>
+</dd><dt id="bib-OWL2-OVERVIEW">[OWL2-OVERVIEW]</dt><dd rel="dcterms:references">W3C OWL Working Group. <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/"><cite>OWL 2 Web Ontology Language: Overview.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/">http://www.w3.org/TR/2009/REC-owl2-overview-20091027/</a>
+</dd><dt id="bib-RDF-MT">[RDF-MT]</dt><dd rel="dcterms:references">Patrick Hayes. <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210"><cite>RDF Semantics.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210">http://www.w3.org/TR/2004/REC-rdf-mt-20040210</a>
+</dd><dt id="bib-RDF-PRIMER">[RDF-PRIMER]</dt><dd rel="dcterms:references">Frank Manola; Eric Miller. <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/"><cite>RDF Primer.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">http://www.w3.org/TR/2004/REC-rdf-primer-20040210/</a>
+</dd><dt id="bib-RDF-SCHEMA">[RDF-SCHEMA]</dt><dd rel="dcterms:references">Dan Brickley; Ramanathan V. Guha. <a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210"><cite>RDF Vocabulary Description Language 1.0: RDF Schema.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">http://www.w3.org/TR/2004/REC-rdf-schema-20040210</a>
+</dd><dt id="bib-RDF-SPARQL-QUERY">[RDF-SPARQL-QUERY]</dt><dd rel="dcterms:references">Andy Seaborne; Eric Prud'hommeaux. <a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115"><cite>SPARQL Query Language for RDF.</cite></a> 15 January 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115">http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115</a>
+</dd><dt id="bib-RDF-SYNTAX-GRAMMAR">[RDF-SYNTAX-GRAMMAR]</dt><dd rel="dcterms:references">Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210"><cite>RDF/XML Syntax Specification (Revised).</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210">http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210</a>
+</dd><dt id="bib-RDF-TESTCASES">[RDF-TESTCASES]</dt><dd rel="dcterms:references">Jan Grant; Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210"><cite>RDF Test Cases.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210">http://www.w3.org/TR/2004/REC-rdf-testcases-20040210</a>
+</dd><dt id="bib-RDFA-PRIMER">[RDFA-PRIMER]</dt><dd rel="dcterms:references">Ben Adida, Ivan Herman, Manu Sporny. <a href="http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607"><cite>RDFa Primer.</cite></a> 07 June 2012. W3C Note. URL: <a href="http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607">http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607</a>
+</dd><dt id="bib-RFC3986">[RFC3986]</dt><dd rel="dcterms:references">T. Berners-Lee; R. Fielding; L. Masinter. <a href="http://www.ietf.org/rfc/rfc3986.txt"><cite>Uniform Resource Identifier (URI): Generic Syntax.</cite></a> January 2005. Internet RFC 3986. URL: <a href="http://www.ietf.org/rfc/rfc3986.txt">http://www.ietf.org/rfc/rfc3986.txt</a>
+</dd><dt id="bib-SWBP-N-ARYRELATIONS">[SWBP-N-ARYRELATIONS]</dt><dd rel="dcterms:references">Natasha Noy; Alan Rector. <a href="http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412"><cite>Defining N-ary Relations on the Semantic Web.</cite></a> 12 April 2006. W3C Note. URL: <a href="http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412">http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412</a>
+</dd><dt id="bib-SWBP-XSCH-DATATYPES">[SWBP-XSCH-DATATYPES]</dt><dd rel="dcterms:references">Jeremy J. Carroll; Jeff Z. Pan. <a href="http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314"><cite>XML Schema Datatypes in RDF and OWL.</cite></a> 14 March 2006. W3C Note. URL: <a href="http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314">http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314</a>
+</dd><dt id="bib-TURTLE-TR">[TURTLE-TR]</dt><dd rel="dcterms:references">Eric Prud'hommeaux, Gavin Carothers. <a href="http://www.w3.org/TR/2012/WD-turtle-20120710/"><cite>Turtle: Terse RDF Triple Language.</cite></a> 10 July 2012. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2012/WD-turtle-20120710/">http://www.w3.org/TR/2012/WD-turtle-20120710/</a>
+</dd><dt id="bib-VOCAB-ORG">[VOCAB-ORG]</dt><dd rel="dcterms:references">Dave Reynolds. <a href="http://www.w3.org/TR/2012/WD-vocab-org-20121023/"><cite>An organization ontology.</cite></a> 23 October 2012. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2012/WD-vocab-org-20121023/">http://www.w3.org/TR/2012/WD-vocab-org-20121023/</a>
+</dd><dt id="bib-WEBARCH">[WEBARCH]</dt><dd rel="dcterms:references">Norman Walsh; Ian Jacobs. <a href="http://www.w3.org/TR/2004/REC-webarch-20041215/"><cite>Architecture of the World Wide Web, Volume One.</cite></a> 15 December 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-webarch-20041215/">http://www.w3.org/TR/2004/REC-webarch-20041215/</a>
+</dd><dt id="bib-WELL-KNOWN">[WELL-KNOWN]</dt><dd rel="dcterms:references">M. Nottingham; E. Hammer-Lahav. <a href="http://tools.ietf.org/html/rfc5785"><cite>Defining Well-Known Uniform Resource Identifiers (URIs).</cite></a> April 2010. Internet RFC 5785. URL: <a href="http://tools.ietf.org/html/rfc5785">http://tools.ietf.org/html/rfc5785</a>
+</dd><dt id="bib-XML-ID">[XML-ID]</dt><dd rel="dcterms:references">Daniel Veillard; Jonathan Marsh; Norman Walsh. <a href="http://www.w3.org/TR/2005/REC-xml-id-20050909"><cite>xml:id Version 1.0.</cite></a> 9 September 2005. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2005/REC-xml-id-20050909">http://www.w3.org/TR/2005/REC-xml-id-20050909</a>
+</dd><dt id="bib-XMLSCHEMA11-1">[XMLSCHEMA11-1]</dt><dd rel="dcterms:references">C. M. Sperberg-McQueen; Henry S. Thompson; Shudi Gao. <a href="http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/"><cite>W3C XML Schema Definition Language (XSD) 1.1 Part 1: Structures.</cite></a> 5 April 2012. W3C Recommendation URL: <a href="http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/">http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/</a>
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-
-</style><link href="https://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css" charset="utf-8" /></head>
-
- <body style="display: inherit; "><div class="head"><p><a href="http://www.w3.org/"><img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" /></a></p><h1 property="dcterms:title" class="title" id="title">RDF 1.1 Concepts and Abstract Syntax</h1><h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-01-15T00:00:00+0000" id="w3c-working-draft-15-january-2013"><acronym title="World Wide Web Consortium">W3C</acronym> Working Draft 15 January 2013</h2><dl><dt>This version:</dt><dd><a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/">http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/</a></dd><dt>Latest published version:</dt><dd><a href="http://www.w3.org/TR/rdf11-concepts/">http://www.w3.org/TR/rdf11-concepts/</a></dd><dt>Latest editor's draft:</dt><dd><a href="http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html">http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html</a></dd><dt>Previous version:</dt><dd><a rel="dcterms:replaces" href="http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/">http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/</a></dd><dt>Latest recommendation:</dt><dd><a href="http://www.w3.org/TR/rdf-concepts/">http://www.w3.org/TR/rdf-concepts/</a></dd><dt>Editors:</dt><dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Richard Cyganiak" href="http://richard.cyganiak.de/">Richard Cyganiak</a>, <a rel="foaf:workplaceHomepage" href="http://www.deri.ie/">DERI, NUI Galway</a></span>
-</dd>
-<dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><span property="foaf:name">David Wood</span>, <a rel="foaf:workplaceHomepage" href="http://www.3roundstones.com/">3 Round Stones</a></span>
-</dd>
-<dt>Previous editors:</dt><dd><span><span>Graham Klyne</span>, Nine by Nine</span>
-</dd>
-<dd><span><span>Jeremy J. Carroll</span>, Hewlett Packard Labs</span>
-</dd>
-<dd><span><span>Brian McBride</span>, Hewlett Packard Labs (RDF 2004 Series Editor)</span>
-</dd>
-</dl><p class="copyright"><a rel="license" href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2004-2013 <span rel="dcterms:publisher"><span typeof="foaf:Organization"><a rel="foaf:homepage" property="foaf:name" content="World Wide Web Consortium" href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup></span></span> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. <acronym title="World Wide Web Consortium">W3C</acronym> <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p><hr /></div>
-
-<div id="abstract" class="introductory section" property="dcterms:abstract" datatype="" typeof="bibo:Chapter" resource="#abstract" rel="bibo:chapter"><h2>Abstract</h2>
- <p>The Resource Description Framework (RDF) is a framework for
- representing information in the Web.</p>
- <p>RDF 1.1 Concepts and Abstract Syntax defines an abstract syntax
- (a data model) which serves to link all RDF-based languages and
- specifications. The abstract syntax has two key data structures:
- RDF graphs are sets of subject-predicate-object triples,
- where the elements may be IRIs, blank nodes, or datatyped literals. They
- are used to express descriptions of resources. RDF datasets are used
- to organize collections of RDF graphs, and comprise a default graph
- and zero or more named graphs.
- This document also introduces key concepts and terminology, and discusses
- datatyping and the handling of fragment identifiers in IRIs within
- RDF graphs.</p>
-</div><div id="sotd" class="introductory section" typeof="bibo:Chapter" resource="#sotd" rel="bibo:chapter"><h2>Status of This Document</h2><p><em>This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current <acronym title="World Wide Web Consortium">W3C</acronym> publications and the latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/"><acronym title="World Wide Web Consortium">W3C</acronym> technical reports index</a> at http://www.w3.org/TR/.</em></p>
- <p>This document is a snapshot of the
- <a href="http://www.w3.org/2011/rdf-wg/">RDF Working Group</a>'s
- progress towards updating the RDF data model for RDF 1.1.
- A <a href="#changes-wd3">list of changes</a> since the
- <a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20120605/">previous working draft</a>
- is provided as an appendix.
- The most significant normative change in this Working Draft
- is the adoption of the concepts of
- <a href="#section-dataset">RDF Dataset</a> and
- <a href="#dfn-named-graph">named graph</a> from
- <a href="http://www.w3.org/TR/sparql11-query/">SPARQL</a>.
- The <a href="#section-Introduction">introduction</a> has seen
- major changes, as have various informative notes
- throughout the document.
- Various areas of ongoing work are marked throughout the text,
- in particular the definitions of
- <a href="#section-blank-nodes">blank nodes</a>,
- <a href="#dfn-ill-typed">ill-typed literals</a>,
- <a href="#section-dataset">operations on RDF datasets</a>,
- and the <a href="#section-fragID">relation of RDF datasets to
- aspects of web architecture</a>.</p>
-<p>This document was published by the <a href="http://www.w3.org/2011/rdf-wg/">RDF Working Group</a> as a Working Draft. This document is intended to become a <acronym title="World Wide Web Consortium">W3C</acronym> Recommendation. If you wish to make comments regarding this document, please send them to <a href="mailto:public-rdf-comments@w3.org">public-rdf-comments@w3.org</a> (<a href="mailto:public-rdf-comments-request@w3.org?subject=subscribe">subscribe</a>, <a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">archives</a>). All feedback is welcome.</p><p>Publication as a Working Draft does not imply endorsement by the <acronym title="World Wide Web Consortium">W3C</acronym> Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.</p><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <acronym title="World Wide Web Consortium">W3C</acronym> Patent Policy</a>. <acronym title="World Wide Web Consortium">W3C</acronym> maintains a <a href="http://www.w3.org/2004/01/pp-impl/46168/status" rel="disclosure">public list of any patent disclosures</a> made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the <acronym title="World Wide Web Consortium">W3C</acronym> Patent Policy</a>.</p></div><div id="toc" typeof="bibo:Chapter" resource="#toc" rel="bibo:chapter" class="section"><h2 class="introductory">Table of Contents</h2><ul class="toc"><li class="tocline"><a href="#section-Introduction" class="tocxref"><span class="secno">1 </span>Introduction</a><ul class="toc"><li class="tocline"><a href="#data-model" class="tocxref"><span class="secno">1.1 </span>Graph-based Data Model</a></li><li class="tocline"><a href="#resources-and-statements" class="tocxref"><span class="secno">1.2 </span>Resources and Statements</a></li><li class="tocline"><a href="#referents" class="tocxref"><span class="secno">1.3 </span>The Referent of an <acronym title="Internationalized Resource Identifier">IRI</acronym></a></li><li class="tocline"><a href="#vocabularies" class="tocxref"><span class="secno">1.4 </span>RDF Vocabularies and Namespace IRIs</a></li><li class="tocline"><a href="#change-over-time" class="tocxref"><span class="secno">1.5 </span>RDF and Change Over Time</a></li><li class="tocline"><a href="#managing-graphs" class="tocxref"><span class="secno">1.6 </span>Working with Multiple RDF Graphs</a></li><li class="tocline"><a href="#entailment" class="tocxref"><span class="secno">1.7 </span>Equivalence, Entailment and Inconsistency</a></li><li class="tocline"><a href="#rdf-documents" class="tocxref"><span class="secno">1.8 </span>RDF Documents and Syntaxes</a></li></ul></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">2 </span>Conformance</a></li><li class="tocline"><a href="#section-rdf-graph" class="tocxref"><span class="secno">3 </span>RDF Graphs</a><ul class="toc"><li class="tocline"><a href="#section-triples" class="tocxref"><span class="secno">3.1 </span>Triples</a></li><li class="tocline"><a href="#section-IRIs" class="tocxref"><span class="secno">3.2 </span>IRIs</a></li><li class="tocline"><a href="#section-Graph-Literal" class="tocxref"><span class="secno">3.3 </span>Literals</a></li><li class="tocline"><a href="#section-blank-nodes" class="tocxref"><span class="secno">3.4 </span>Blank Nodes</a></li><li class="tocline"><a href="#section-skolemization" class="tocxref"><span class="secno">3.5 </span>Replacing Blank Nodes with IRIs</a></li><li class="tocline"><a href="#graph-isomorphism" class="tocxref"><span class="secno">3.6 </span>Graph Isomorphism</a></li></ul></li><li class="tocline"><a href="#section-dataset" class="tocxref"><span class="secno">4 </span>RDF Datasets</a></li><li class="tocline"><a href="#section-Datatypes" class="tocxref"><span class="secno">5 </span>Datatypes</a><ul class="toc"><li class="tocline"><a href="#xsd-datatypes" class="tocxref"><span class="secno">5.1 </span>The XML Schema Built-in Datatypes</a></li><li class="tocline"><a href="#section-html" class="tocxref"><span class="secno">5.2 </span>The <code>rdf:HTML</code> Datatype</a></li><li class="tocline"><a href="#section-XMLLiteral" class="tocxref"><span class="secno">5.3 </span>The <code>rdf:XMLLiteral</code> Datatype</a></li><li class="tocline"><a href="#datatype-maps" class="tocxref"><span class="secno">5.4 </span>Datatype Maps</a></li><li class="tocline"><a href="#section-Literal-Value" class="tocxref"><span class="secno">5.5 </span>The Value Corresponding to a Literal</a></li></ul></li><li class="tocline"><a href="#section-fragID" class="tocxref"><span class="secno">6 </span>Fragment Identifiers</a></li><li class="tocline"><a href="#section-Acknowledgments" class="tocxref"><span class="secno">7 </span>Acknowledgments</a></li><li class="tocline"><a href="#changes" class="tocxref"><span class="secno">A </span>Changes between RDF 2004 and RDF 1.1</a></li><li class="tocline"><a href="#change-log" class="tocxref"><span class="secno">B </span>Change Log</a><ul class="toc"><li class="tocline"><a href="#changes-wd3" class="tocxref"><span class="secno">B.1 </span>Changes from 05 June 2012 WD to this version</a></li><li class="tocline"><a href="#changes-wd2" class="tocxref"><span class="secno">B.2 </span>Changes from FPWD to 05 June 2012 WD</a></li><li class="tocline"><a href="#changes-fpwd" class="tocxref"><span class="secno">B.3 </span>Changes from RDF 2004 to FPWD</a></li></ul></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></div>
-
-
-
-
-
-<div id="section-Introduction" class="informative section" typeof="bibo:Chapter" resource="#section-Introduction" rel="bibo:chapter">
- <h2><span class="secno">1 </span>Introduction</h2><p><em>This section is non-normative.</em></p>
-
- <p class="issue">This is a work-in-progress Working Draft. Various open
- issues are flagged throughout the text with boxes like this.
- <a href="#sotd">Feedback</a> on these issues is particularly welcome.</p>
-
- <p>The <em>Resource Description Framework</em> (RDF) is a framework
- for representing information in the Web.</p>
-
- <p>This document defines an abstract syntax (a data model)
- which serves to link all RDF-based languages and specifications,
- including:</p>
-
- <ul>
- <li>serialization syntaxes for storing and exchanging RDF
- (e.g., <a href="http://www.w3.org/TR/turtle/">Turtle</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE-TR">TURTLE-TR</a></cite>]
- and <a href="http://www.w3.org/TR/REC-rdf-syntax/">RDF/XML</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>]),</li>
-
- <li>the <a href="http://www.w3.org/TR/rdf-sparql-query/">SPARQL
- Query Language</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SPARQL-QUERY">RDF-SPARQL-QUERY</a></cite>],</li>
-
- <li>the <a href="http://www.w3.org/TR/rdf-schema/">RDF Vocabulary
- Description Language</a> (RDFS) [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>],</li>
-
- <li>the <a href="http://www.w3.org/TR/rdf-mt/">formal
- model-theoretic semantics for RDF and RDFS</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>].</li>
- </ul>
-
-<div id="data-model" typeof="bibo:Chapter" resource="#data-model" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.1 </span>Graph-based Data Model</h3>
-
- <p>The core structure of the abstract syntax is a set of
- <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a>, each consisting of a <a href="#dfn-subject" class="internalDFN">subject</a>,
- a <a href="#dfn-predicate" class="internalDFN">predicate</a> and an <a href="#dfn-object" class="internalDFN">object</a>. A set of such triples is called
- an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>. An RDF graph can be visualized as a node and
- directed-arc diagram, in which each triple is represented as a
- node-arc-node link.</p>
-
- <div class="figure">
- <a href="rdf-graph.png"><img src="rdf-graph.svg" alt="An RDF graph with two nodes (Subject and Object) and a triple connecting them (Predicate)" /></a>
- </div>
-
- <p>There can be three kinds of <a title="node" href="#dfn-node" class="internalDFN">nodes</a> in an
- <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>: <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>,
- and <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a>.</p>
-</div>
-
-
-<div id="resources-and-statements" typeof="bibo:Chapter" resource="#resources-and-statements" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.2 </span>Resources and Statements</h3>
-
- <p>Any <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> or <a href="#dfn-literal" class="internalDFN">literal</a> <dfn title="denote" id="dfn-denote">denotes</dfn>
- some thing in the universe of discourse. These things are called
- <dfn title="resource" id="dfn-resource">resources</dfn>. Anything can be a resource,
- including physical things, documents, abstract concepts, numbers
- and strings; the term is synonymous with “entity”.
- The resource denoted by an <acronym title="Internationalized Resource Identifier">IRI</acronym> is called its <a href="#dfn-referent" class="internalDFN">referent</a>, and the
- resource denoted by a literal is called its
- <a title="literal value" href="#dfn-literal-value" class="internalDFN">literal value</a>. Literals have
- <a title="datatype" href="#dfn-datatype" class="internalDFN">datatypes</a> that define the range of possible
- values, such as strings, numbers, and dates. A special kind of literals,
- <a>language-tagged strings</a>, denote plain-text strings in a
- natural language.</p>
-
- <p>The assertion of an <a href="#dfn-rdf-triple" class="internalDFN">RDF triple</a> says that <em>some relationship,
- indicated by the <a href="#dfn-predicate" class="internalDFN">predicate</a>, holds between the
- <a title="resource" href="#dfn-resource" class="internalDFN">resources</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by
- the <a href="#dfn-subject" class="internalDFN">subject</a> and <a href="#dfn-object" class="internalDFN">object</a></em>. This statement corresponding
- to an RDF triple is known as an <dfn id="dfn-rdf-statement">RDF statement</dfn>.
- The predicate itself is an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> and denotes a <dfn id="dfn-property">property</dfn>,
- that is, a <a href="#dfn-resource" class="internalDFN">resource</a> that can be thought of as a binary relation.
- (Relations that involve more than two entities can only be
- <a href="http://www.w3.org/TR/swbp-n-aryRelations/">indirectly
- expressed in RDF</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-SWBP-N-ARYRELATIONS">SWBP-N-ARYRELATIONS</a></cite>].)</p>
-
- <p>Unlike <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>,
- <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a> do not denote specific
- <a title="resource" href="#dfn-resource" class="internalDFN">resources</a>.
- <a title="RDF statement" href="#dfn-rdf-statement" class="internalDFN">Statements</a> involving
- blank nodes say that something with the given
- relationships exists, without explicitly naming it.</p>
-</div>
-
-
-<div id="referents" typeof="bibo:Chapter" resource="#referents" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.3 </span>The Referent of an <acronym title="Internationalized Resource Identifier">IRI</acronym></h3>
-
- <p>The <a href="#dfn-resource" class="internalDFN">resource</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>
- is also called its <dfn id="dfn-referent">referent</dfn>.
- What exactly is denoted by any given <acronym title="Internationalized Resource Identifier">IRI</acronym> is not defined by this
- specification.</p>
-
- <p>Guidelines for determining the <a href="#dfn-referent" class="internalDFN">referent</a> of an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> are
- provided in other documents, like
- <em><a href="http://www.w3.org/TR/webarch/">Architecture of the
- World Wide Web, Volume One</a></em> [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] and
- <em><a href="http://www.w3.org/TR/cooluris/">Cool URIs for the
- Semantic Web</a></em> [<cite><a class="bibref" rel="biblioentry" href="#bib-COOLURIS">COOLURIS</a></cite>].
- A very brief, informal and partial account follows:</p>
-
- <ul>
- <li>IRIs have global scope: An <acronym title="Internationalized Resource Identifier">IRI</acronym> is assumed to <a href="#dfn-denote" class="internalDFN">denote</a>
- the same <a href="#dfn-resource" class="internalDFN">resource</a> regardless of where the <acronym title="Internationalized Resource Identifier">IRI</acronym> occurs.</li>
-
- <li>By social convention, the
- <a href="http://www.w3.org/TR/webarch/#uri-ownership"><acronym title="Internationalized Resource Identifier">IRI</acronym> owner</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] gets to say what an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> <a title="denote" href="#dfn-denote" class="internalDFN">denotes</a>.
- They do this when “<dfn id="dfn-minting">minting</dfn>” a new <acronym title="Internationalized Resource Identifier">IRI</acronym>.</li>
-
- <li>The <acronym title="Internationalized Resource Identifier">IRI</acronym> owner can establish the intended <a href="#dfn-referent" class="internalDFN">referent</a>
- by means of a specification or other document that explains
- what is denoted. For example, the
- <a href="http://www.w3.org/TR/vocab-org/">Organization Ontology
- document</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-VOCAB-ORG">VOCAB-ORG</a></cite>] specifies the referents
- of various IRIs that start with
- <code>http://www.w3.org/ns/org#</code>.</li>
-
- <li>A good way of communicating the intended referent
- is to set up the <acronym title="Internationalized Resource Identifier">IRI</acronym> so that it
- <a href="http://www.w3.org/TR/webarch/#uri-dereference">dereferences</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] to such a document.</li>
-
- <li>Such a document can, in fact, be an <a href="#dfn-rdf-document" class="internalDFN">RDF document</a>
- that describes the denoted resource by means of
- <a title="RDF statement" href="#dfn-rdf-statement" class="internalDFN">RDF statements</a>.</li>
- </ul>
-
- <p>Perhaps the most important characterisitic of <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>
- in web architecture is that they can be
- <a href="http://www.w3.org/TR/webarch/#uri-dereference">dereferenced</a>,
- and hence serve as starting points for interactions with a remote server.
- This specification, however, is not concerned with such interactions.
- It does not define an interaction model. It only treats IRIs as globally
- unique identifiers in a graph data model that describes resources.</p>
-</div>
-
-<div id="vocabularies" typeof="bibo:Chapter" resource="#vocabularies" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.4 </span>RDF Vocabularies and Namespace IRIs</h3>
-
- <p>An <dfn id="dfn-rdf-vocabulary">RDF vocabulary</dfn> is a collection of <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>
- with clearly established <a title="referent" href="#dfn-referent" class="internalDFN">referents</a>
- intended for use in <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. For example,
- the IRIs documented in [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>] are the RDF Schema vocabulary.
- RDF Schema can itself be used to define and document additional
- RDF vocabularies. Some such vocabularies are mentioned in the
- Primer [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-PRIMER">RDF-PRIMER</a></cite>].</p>
-
- <p>The <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> in an <a href="#dfn-rdf-vocabulary" class="internalDFN">RDF vocabulary</a> often share
- a common substring known as a <dfn id="dfn-namespace-iri">namespace <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>.
- Some namespace IRIs are associated by convention with a short name
- known as a <dfn id="dfn-namespace-prefix">namespace prefix</dfn>. Some examples:
-
- </p><table rules="all" summary="Some example namespace prefixes and IRIs">
- <tbody><tr><th>Namespace prefix</th><th>Namespace <acronym title="Internationalized Resource Identifier">IRI</acronym></th><th>RDF vocabulary</th></tr>
- <tr><td>rdf</td><td><a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><code>http://www.w3.org/1999/02/22-rdf-syntax-ns#</code></a></td><td>The RDF built-in vocabulary [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]</td></tr>
- <tr><td>rdfs</td><td><a href="http://www.w3.org/2000/01/rdf-schema#"><code>http://www.w3.org/2000/01/rdf-schema#</code></a></td><td>The RDF Schema vocabulary [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]</td></tr>
- <tr><td>xsd</td><td><a href="http://www.w3.org/2001/XMLSchema#"><code>http://www.w3.org/2001/XMLSchema#</code></a></td><td>The <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a></td></tr>
- </tbody></table>
-
- <p>In some contexts it is common to abbreviate <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>
- that start with <a title="namespace IRI" href="#dfn-namespace-iri" class="internalDFN">namespace IRIs</a> by using the
- associated <a href="#dfn-namespace-prefix" class="internalDFN">namespace prefix</a>. For example, the <acronym title="Internationalized Resource Identifier">IRI</acronym>
- <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>
- would be abbreviated as <code>rdf:XMLLiteral</code>.
- Note however that these abbreviations are <em>not</em> valid IRIs,
- and must not be used in contexts where IRIs are expected.
- Namespace IRIs and namespace prefixes are <em>not</em> a formal part of the
- RDF data model. They are merely a syntactic convenience for
- abbreviating IRIs.</p>
-
- <p>The term “<dfn id="dfn-namespace">namespace</dfn>” on its own does not have a
- well-defined meaning in the context of RDF, but is sometimes informally
- used to mean “<a href="#dfn-namespace-iri" class="internalDFN">namespace <acronym title="Internationalized Resource Identifier">IRI</acronym></a>” or “<a href="#dfn-rdf-vocabulary" class="internalDFN">RDF vocabulary</a>”.</p>
-</div>
-
-
-<div id="change-over-time" typeof="bibo:Chapter" resource="#change-over-time" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.5 </span>RDF and Change Over Time</h3>
-
- <p>The RDF data model is <em>atemporal</em>: It does not deal with time,
- and does not have a built-in notion of temporal validity of information.
- <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> are static snapshots of
- information.</p>
-
- <p>However, <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> can express information
- about events and about temporal aspects of other entities,
- given appropriate <a title="RDF vocabulary" href="#dfn-rdf-vocabulary" class="internalDFN">vocabulary</a> terms.</p>
-
- <p>Since <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> are defined as mathematical
- sets, adding or removing <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a> from an
- RDF graph yields a different RDF graph.</p>
-
- <p>We informally use the term <dfn id="dfn-rdf-source">RDF source</dfn> to refer to a
- persistent yet mutable source or container of
- <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. An RDF source is a <a href="#dfn-resource" class="internalDFN">resource</a>
- that may be said to have a state that can change over time.
- A snapshot of the state can be expressed as an RDF graph.
- For example, any web document that has an RDF-bearing representation
- may be considered an RDF source. Like all resources, RDF sources may
- be named with <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and therefore described in
- other RDF graphs.</p>
-
- <p>Intuitively speaking, changes in the universe of discourse
- can be reflected in the following ways:</p>
-
- <ul>
- <li>An <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>, once <a title="minting" href="#dfn-minting" class="internalDFN">minted</a>, should never
- change its <a href="#dfn-referent" class="internalDFN">referent</a>. (See
- <a href="http://www.w3.org/TR/webarch/#URI-persistence"><acronym title="Uniform Resource Identifier">URI</acronym>
- persistence</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>].)</li>
- <li><a title="literal" href="#dfn-literal" class="internalDFN">Literals</a>, by design, are constants and
- never change their <a title="literal value" href="#dfn-literal-value" class="internalDFN">value</a>.</li>
- <li>Some <a title="property" href="#dfn-property" class="internalDFN">properties</a> may change over time.
- A relationship that holds between two <a title="resource" href="#dfn-resource" class="internalDFN">resources</a>
- at one time may not hold at another time.</li>
- <li><a title="RDF source" href="#dfn-rdf-source" class="internalDFN">RDF sources</a> may change their state
- over time.
- That is, they may provide different <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>
- at different times.</li>
- <li>Some <a title="RDF source" href="#dfn-rdf-source" class="internalDFN">RDF sources</a> may, however, be immutable
- snapshots of another RDF source, archiving its state at some
- point in time.</li>
- </ul>
-
-</div>
-
-
-<div id="managing-graphs" typeof="bibo:Chapter" resource="#managing-graphs" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.6 </span>Working with Multiple RDF Graphs</h3>
-
- <p>As RDF graphs are sets of triples, they can be
- <a title="merge" href="#dfn-merge" class="internalDFN">merged</a> easily, supporting the use of data from
- multiple sources. Nevertheless, it is sometimes desirable to work
- with multiple RDF graphs while keeping their contents separate.
- <a title="RDF dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a> support this requirement.</p>
-
- <p>An <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a> is a collection of
- <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. All but one of these graphs have
- an associated <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>. They are called
- <a title="named graph" href="#dfn-named-graph" class="internalDFN">named graphs</a>, and the <acronym title="Internationalized Resource Identifier">IRI</acronym> is called the
- <a href="#dfn-graph-name" class="internalDFN">graph name</a>.
- The remaining graph does not have an associated <acronym title="Internationalized Resource Identifier">IRI</acronym>, and is called
- the <a href="#dfn-default-graph" class="internalDFN">default graph</a> of the RDF dataset.</p>
-
- <p>There are many possible uses for <a title="RDF dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a>.
- One such use is to hold snapshots of multiple
- <a title="RDF source" href="#dfn-rdf-source" class="internalDFN">RDF sources</a>. It is common to have the
- <a href="#dfn-default-graph" class="internalDFN">default graph</a> contain <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a>
- that involve the <a title="graph name" href="#dfn-graph-name" class="internalDFN">graph names</a>
- of the other graphs in the dataset.</p>
-</div>
-
-
-<div id="entailment" typeof="bibo:Chapter" resource="#entailment" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.7 </span>Equivalence, Entailment and Inconsistency</h3>
-
- <p class="issue">No Editor's Draft of <em>RDF 1.1 Semantics</em> is
- available yet
- (<a href="https://www.w3.org/2011/rdf-wg/track/actions/214">ACTION-214</a>),
- and its relationship to this document is not yet
- entirely clear. Some Semantics-related material may be moved here,
- in particular the definition of <dfn title="merge" id="dfn-merge">graph merge</dfn> and
- <dfn id="dfn-subgraph">subgraph</dfn>, and informative
- <a href="http://www.w3.org/TR/rdf-mt/#rules">entailment rules</a>
- for the entailments over the RDF data model
- (excluding any specific vocabulary). This is
- <a href="https://www.w3.org/2011/rdf-wg/track/issues/106">ISSUE-106</a>.</p>
-
- <p class="issue">The Working Group intends to publish a Working Group
- Note detailing some of its efforts to define a <strong>formal semantics for
- RDF datasets</strong>. It should be referenced here when available. This is
- <a href="http://www.w3.org/2011/rdf-wg/track/actions/209">ACTION-209</a>.
- </p>
-
- <p>An <a href="#dfn-rdf-triple" class="internalDFN">RDF triple</a> encodes a <a title="RDF statement" href="#dfn-rdf-statement" class="internalDFN">statement</a>—a
- simple <dfn id="dfn-logical-expression">logical expression</dfn>, or claim about the world.
- An <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> is the conjunction (logical <em>AND</em>) of
- its triples, and the conjunction of two RDF graphs is their <a href="#dfn-merge" class="internalDFN">merge</a>.
- This treatment of RDF graphs as logical expressions is
- normatively defined in the
- <a href="http://www.w3.org/TR/rdf-mt/">RDF Semantics</a>
- specification [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>], using a model-theoretic semantics.
- It yields various relationships between RDF graphs:</p>
-
- <dl>
- <dt><dfn id="dfn-entailment">Entailment</dfn></dt>
- <dd>An <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> <em>A</em> entails another RDF graph <em>B</em>
- if every possible arrangement of the world
- that makes <em>A</em> true also makes <em>B</em> true. When <em>A</em>
- entails <em>B</em>, if the truth of <em>A</em> is presumed or demonstrated
- then the truth of <em>B</em> is established.</dd>
-
- <dt><dfn id="dfn-equivalence">Equivalence</dfn></dt>
- <dd>Two <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> <em>A</em> and <em>B</em>
- are equivalent if they make the same claim about the world.
- <em>A</em> is equivalent to <em>B</em> if and only if
- <em>A</em> <a title="entailment" href="#dfn-entailment" class="internalDFN">entails</a> <em>B</em> and
- <em>B</em> entails <em>A</em>.</dd>
-
- <dt><dfn id="dfn-inconsistency">Inconsistency</dfn></dt>
- <dd>An <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> is inconsistent if it contains
- an internal contradiction. There is no possible arrangement
- of the world that would make the expression true.</dd>
- </dl>
-
- <p>An <dfn id="dfn-entailment-regime">entailment regime</dfn> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>] is a specification that
- defines precise conditions that make these relationships hold.
- RDF itself recognizes only some basic cases of entailment, equivalence
- and inconsistency. Other specifications, such as
- <a href="http://www.w3.org/TR/rdf-schema/">RDF Schema</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]
- and <a href="http://www.w3.org/TR/owl2-overview/">OWL 2</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>], add more powerful entailment regimes,
- as do some domain-specific <a title="RDF vocabulary" href="#dfn-rdf-vocabulary" class="internalDFN">vocabularies</a>.
- Some entailment regimes are defined with respect to a
- <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>.</p>
-
- <p>This specification does not constrain how implementations
- use the logical relationships defined by
- <a title="entailment regime" href="#dfn-entailment-regime" class="internalDFN">entailment regimes</a>.
- Implementations may or may not detect
- <a title="inconsistency" href="#dfn-inconsistency" class="internalDFN">inconsistencies</a>, and may make all,
- some or no <a title="entailment" href="#dfn-entailment" class="internalDFN">entailed</a> information
- available to users.</p>
-</div>
-
-
-<div id="rdf-documents" typeof="bibo:Chapter" resource="#rdf-documents" rel="bibo:chapter" class="section">
- <h3><span class="secno">1.8 </span>RDF Documents and Syntaxes</h3>
-
- <p>An <dfn id="dfn-rdf-document">RDF document</dfn> is a document that encodes an
- <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> or <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a> in a <dfn id="dfn-concrete-rdf-syntax">concrete RDF syntax</dfn>,
- such as Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE-TR">TURTLE-TR</a></cite>], RDFa [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-PRIMER">RDFA-PRIMER</a></cite>],
- RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>], or N-Triples [<cite><a class="bibref" rel="biblioentry" href="#bib-N-TRIPLES">N-TRIPLES</a></cite>].
- RDF documents enable the exchange of RDF graphs and RDF datasets
- between systems.</p>
-
- <p>A <a href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntax</a><a> may offer
- many different ways to encode the same </a><a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> or
- <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>, for example through the use of
- <a title="namespace prefix" href="#dfn-namespace-prefix" class="internalDFN">namespace prefixes</a>,
- relative IRIs, <a title="blank node identifier" href="#dfn-blank-node-identifier" class="internalDFN">blank node identifiers</a>,
- and different ordering of statements. While these aspects can have great
- effect on the convenience of working with the <a href="#dfn-rdf-document" class="internalDFN">RDF document</a>,
- they are not significant for its meaning.</p>
-</div>
-
-
-</div>
-
-
-<div id="conformance" typeof="bibo:Chapter" resource="#conformance" rel="bibo:chapter" class="section"><h2><span class="secno">2 </span>Conformance</h2><p>As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.</p>
-<p>The key words <em class="rfc2119" title="must">must</em>, <em class="rfc2119" title="must not">must not</em>, <em class="rfc2119" title="required">required</em>, <em class="rfc2119" title="should">should</em>, <em class="rfc2119" title="should not">should not</em>, <em class="rfc2119" title="recommended">recommended</em>, <em class="rfc2119" title="may">may</em>, and <em class="rfc2119" title="optional">optional</em> in this specification are to be interpreted as described in [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC2119">RFC2119</a></cite>].</p>
-
- <p>This specification, <em>RDF 1.1 Concepts and Abstract Syntax</em>,
- defines a data model and related terminology for use in
- other specifications, such as
- <a title="concrete RDF syntax" href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntaxes</a>,
- API specifications, and query languages.
- Implementations cannot directly conform to
- <em>RDF 1.1 Concepts and Abstract Syntax</em>,
- but can conform to such other specifications that normatively
- reference terms defined here.</p>
-</div>
-
-
-<div id="section-rdf-graph" typeof="bibo:Chapter" resource="#section-rdf-graph" rel="bibo:chapter" class="section">
- <h2><span class="secno">3 </span>RDF Graphs</h2>
-
- <p>An <dfn id="dfn-rdf-graph">RDF graph</dfn> is a set of
- <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">RDF triples</a>.</p>
-
-
-<div id="section-triples" typeof="bibo:Chapter" resource="#section-triples" rel="bibo:chapter" class="section">
- <h3><span class="secno">3.1 </span>Triples</h3>
-
- <p>An <dfn id="dfn-rdf-triple">RDF triple</dfn> consists of three components:</p>
-
- <ul>
- <li>the <dfn id="dfn-subject">subject</dfn>, which is an
- <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> or a <a href="#dfn-blank-node" class="internalDFN">blank node</a></li>
-
- <li>the <dfn id="dfn-predicate">predicate</dfn>, which is an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a></li>
-
- <li>the <dfn id="dfn-object">object</dfn>, which is an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>,
- a <a href="#dfn-literal" class="internalDFN">literal</a> or a <a href="#dfn-blank-node" class="internalDFN">blank node</a></li>
- </ul>
-
- <p>An RDF triple is conventionally written in the order subject,
- predicate, object.</p>
-
- <p>The set of <dfn title="node" id="dfn-node">nodes</dfn> of an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>
- is the set of subjects and objects of triples in the graph.
- It is possible for a predicate <acronym title="Internationalized Resource Identifier">IRI</acronym> to also occur as a node in
- the same graph.</p>
-
- <p><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> and
- <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a> are collectively known as
- <dfn title="RDF term" id="dfn-rdf-term">RDF terms</dfn>.</p>
-
- <p class="note"><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>
- and <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a> are distinct and distinguishable.
- For example, <code>http://example.org/</code> as a string literal
- is not equal to <code>http://example.org/</code> as an <acronym title="Internationalized Resource Identifier">IRI</acronym>,
- nor to a blank node with the <a href="#dfn-blank-node-identifier" class="internalDFN">blank node identifier</a>
- <code>http://example.org/</code>.</p>
-</div>
-
-
-<div id="section-IRIs" typeof="bibo:Chapter" resource="#section-IRIs" rel="bibo:chapter" class="section">
- <h3><span class="secno">3.2 </span>IRIs</h3>
-
- <p>An <dfn title="IRI" id="dfn-iri"><acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>
- (Internationalized Resource Identifier) within an RDF graph
- is a Unicode string [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] that conforms to the syntax
- defined in RFC 3987 [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>].</p>
-
- <p>IRIs in the RDF abstract syntax <em class="rfc2119" title="must">must</em> be absolute, and <em class="rfc2119" title="may">may</em>
- contain a fragment identifier.</p>
-
- <p><dfn id="dfn-iri-equality"><acronym title="Internationalized Resource Identifier">IRI</acronym> equality</dfn>:
- Two IRIs are equal if and only if they are equivalent
- under Simple String Comparison according to
- <a href="http://tools.ietf.org/html/rfc3987#section-5.1">section 5.1</a>
- of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. Further normalization <em class="rfc2119" title="must not">must not</em> be performed when
- comparing IRIs for equality.</p>
-
- <div class="note" id="note-iris">
- <p><strong>URIs and IRIs:</strong>
- IRIs are a generalization of
- <dfn title="URI" id="dfn-uri"><acronym title="Uniform Resource Identifier">URI</acronym>s</dfn> [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>] that permits a much wider range of Unicode characters.
- Every absolute <acronym title="Uniform Resource Identifier">URI</acronym> and URL is an <acronym title="Internationalized Resource Identifier">IRI</acronym>, but not every <acronym title="Internationalized Resource Identifier">IRI</acronym> is an <acronym title="Uniform Resource Identifier">URI</acronym>.
- When IRIs are used in operations that are only
- defined for URIs, they must first be converted according to
- the mapping defined in
- <a href="http://tools.ietf.org/html/rfc3987#section-3.1">section 3.1</a>
- of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. A notable example is retrieval over the HTTP
- protocol. The mapping involves UTF-8 encoding of non-ASCII
- characters, %-encoding of octets not allowed in URIs, and
- Punycode-encoding of domain names.</p>
-
- <p><strong>Relative IRIs:</strong>
- Some <a title="concrete RDF syntax" href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntaxes</a> permit
- <dfn title="relative IRI" id="dfn-relative-iri">relative IRIs</dfn> as a convenient shorthand
- that allows authoring of documents independently from their final
- publishing location. Relative IRIs must be
- <a href="http://tools.ietf.org/html/rfc3986#section-5.2">resolved
- against</a> a <dfn id="dfn-base-iri">base <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn> to make them absolute.
- Therefore, the RDF graph serialized in such syntaxes is well-defined only
- if a <a href="http://tools.ietf.org/html/rfc3986#section-5.1">base <acronym title="Internationalized Resource Identifier">IRI</acronym>
- can be established</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>].</p>
-
- <p><strong><acronym title="Internationalized Resource Identifier">IRI</acronym> normalization:</strong>
- Interoperability problems can be avoided by minting
- only IRIs that are normalized according to
- <a href="http://tools.ietf.org/html/rfc3987#section-5">Section 5</a>
- of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. Non-normalized forms that are best avoided
- include:</p>
-
- <ul>
- <li>Uppercase characters in scheme names and domain names</li>
- <li>Percent-encoding of characters where it is not
- required by <acronym title="Internationalized Resource Identifier">IRI</acronym> syntax</li>
- <li>Explicitly stated HTTP default port
- (<code>http://example.com:80/</code>);
- <code>http://example.com/</code> is preferrable</li>
- <li>Completely empty path in HTTP IRIs
- (<code>http://example.com</code>);
- <code>http://example.com/</code> is preferrable</li>
- <li>“<code>/./</code>” or “<code>/../</code>” in the path
- component of an <acronym title="Internationalized Resource Identifier">IRI</acronym></li>
- <li>Lowercase hexadecimal letters within percent-encoding
- triplets (“<code>%3F</code>” is preferable over
- “<code>%3f</code>”)</li>
- <li>Punycode-encoding of Internationalized Domain Names
- in IRIs</li>
- <li>IRIs that are not in Unicode Normalization
- Form C [<cite><a class="bibref" rel="biblioentry" href="#bib-NFC">NFC</a></cite>]</li>
- </ul>
- </div>
-</div>
-
-
-<div id="section-Graph-Literal" typeof="bibo:Chapter" resource="#section-Graph-Literal" rel="bibo:chapter" class="section">
- <h3><span class="secno">3.3 </span>Literals</h3>
-
- <p>Literals are used to denote values such as strings, numbers and dates
- by means of a lexical representation.</p>
-
- <p>A <dfn id="dfn-literal">literal</dfn> in an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> consists of two or three
- elements:</p>
-
- <ul>
- <li>a <dfn id="dfn-lexical-form">lexical form</dfn>, being a Unicode [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] string,
- which <em class="rfc2119" title="should">should</em> be in Normal Form C [<cite><a class="bibref" rel="biblioentry" href="#bib-NFC">NFC</a></cite>],</li>
- <li>a <dfn id="dfn-datatype-iri">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>, being an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> that determines
- how the lexical form maps to a <a href="#dfn-literal-value" class="internalDFN">literal value</a>.</li>
- </ul>
-
- <p>A literal is a <dfn id="dfn-language-tagged-string">language-tagged string</dfn> if and only if its
- <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a> is
- <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#langString</code>,
- and only in this case the third element is present:</p>
-
- <ul>
- <li>a non-empty <dfn id="dfn-language-tag">language tag</dfn> as defined by [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>].
- The language tag <em class="rfc2119" title="must">must</em> be well-formed according to
- <a href="http://tools.ietf.org/html/bcp47#section-2.2.9">section 2.2.9</a>
- of [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>], and <em class="rfc2119" title="must">must</em> be normalized to lowercase.</li>
- </ul>
-
- <p>Concrete syntaxes <em class="rfc2119" title="may">may</em> support <dfn title="simple literal" id="dfn-simple-literal">simple
- literals</dfn>, consisting of only a <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>
- without any datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> or language tag. Simple literals only
- exist in concrete syntaxes, and are treated as
- syntactic sugar for abstract syntax
- <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> with the <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a>
- <code>http://www.w3.org/2001/XMLSchema#string</code>.</p>
-
- <p><dfn id="dfn-literal-equality">Literal equality</dfn>:
- Two literals are equal if and only if the two
- <a title="lexical form" href="#dfn-lexical-form" class="internalDFN">lexical forms</a>, the two
- <a title="datatype IRI" href="#dfn-datatype-iri" class="internalDFN">datatype IRIs</a>, and the two
- <a title="language tag" href="#dfn-language-tag" class="internalDFN">language tags</a> (if any)
- compare equal, character by character.</p>
-</div>
-
-
-<div id="section-blank-nodes" typeof="bibo:Chapter" resource="#section-blank-nodes" rel="bibo:chapter" class="section">
- <h3><span class="secno">3.4 </span>Blank Nodes</h3>
-
- <p class="issue">Various proposals have been made for revising
- this section, ranging from editorial re-wordings to major re-writes
- that introduce notions of a “scope” for blank node identifiers
- and define the concept of a “fresh” blank node. This is
- <a href="https://www.w3.org/2011/rdf-wg/track/issues/107">ISSUE-107</a>.</p>
-
- <p>The <dfn title="blank node" id="dfn-blank-node">blank nodes</dfn> in an RDF graph
- are drawn from an infinite set. This set is disjoint from the set
- of all <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and the set of all
- <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>.
- Otherwise, this set of blank nodes is arbitrary.</p>
-
- <p>Given two blank nodes, it is
- possible to determine whether or not they are the same.
- Besides that, RDF makes no reference to any internal structure
- of blank nodes.</p>
-
- <p class="note" id="note-bnode-id">
- <dfn title="blank node identifier" id="dfn-blank-node-identifier">Blank node identifiers</dfn>
- are local identifiers that are used in some
- <a title="concrete RDF syntax" href="#dfn-concrete-rdf-syntax" class="internalDFN">concrete RDF syntaxes</a>
- or RDF store implementations.
- They are always locally scoped to the file or RDF store,
- and are <em>not</em> persistent or portable identifiers
- for blank nodes. Blank node identifiers are <em>not</em>
- part of the RDF abstract syntax, but are entirely dependent
- on the concrete syntax or implementation. The syntactic restrictions
- on blank node identifiers, if any, therefore also depend on
- the concrete RDF syntax or implementation.</p>
-</div>
-
-
-<div id="section-skolemization" typeof="bibo:Chapter" resource="#section-skolemization" rel="bibo:chapter" class="section">
- <h3><span class="secno">3.5 </span>Replacing Blank Nodes with IRIs</h3>
-
- <p>Blank nodes do not have identifiers in the RDF abstract syntax. The
- <a title="blank node identifier" href="#dfn-blank-node-identifier" class="internalDFN">blank node identifiers</a> introduced
- by some concrete syntaxes have only
- local scope and are purely an artifact of the serialization.</p>
-
- <p>In situations where stronger identification is needed, systems <em class="rfc2119" title="may">may</em>
- systematically replace some or all of the blank nodes in an RDF graph
- with <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>. Systems wishing to do this <em class="rfc2119" title="should">should</em>
- <a title="minting" href="#dfn-minting" class="internalDFN">mint</a> a new, globally
- unique <acronym title="Internationalized Resource Identifier">IRI</acronym> (a <dfn id="dfn-skolem-iri">Skolem <acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>) for each blank node so replaced.</p>
-
- <p>This transformation does not appreciably change the meaning of an
- RDF graph, provided that the Skolem IRIs do not occur anywhere else.
- It does however permit the possibility of other graphs
- subsequently using the Skolem IRIs, which is not possible
- for blank nodes.</p>
-
- <p>Systems may wish to mint Skolem IRIs in such a way that they can
- recognize the IRIs as having been introduced solely to replace a blank
- node. This allows the system to map IRIs back to the source blank node
- if needed.</p>
-
- <p>Systems that want Skolem IRIs to be recognizable outside of the system
- boundaries <em class="rfc2119" title="should">should</em> use a well-known <acronym title="Internationalized Resource Identifier">IRI</acronym> [<cite><a class="bibref" rel="biblioentry" href="#bib-WELL-KNOWN">WELL-KNOWN</a></cite>] with the registered
- name <code>genid</code>. This is an <acronym title="Internationalized Resource Identifier">IRI</acronym> that uses the HTTP or HTTPS scheme,
- or another scheme that has been specified to use well-known IRIs; and whose
- path component starts with <code>/.well-known/genid/</code>.
-
- </p><p>For example, the authority responsible for the domain
- <code>example.com</code> could mint the following recognizable Skolem <acronym title="Internationalized Resource Identifier">IRI</acronym>:</p>
-
- <pre>http://example.com/.well-known/genid/d26a2d0e98334696f4ad70a677abc1f6</pre>
-
- <p class="note">RFC 5785 [<cite><a class="bibref" rel="biblioentry" href="#bib-WELL-KNOWN">WELL-KNOWN</a></cite>] only specifies well-known URIs,
- not IRIs. For the purpose of this document, a well-known <acronym title="Internationalized Resource Identifier">IRI</acronym> is any
- <acronym title="Internationalized Resource Identifier">IRI</acronym> that results in a well-known <acronym title="Uniform Resource Identifier">URI</acronym> after <acronym title="Internationalized Resource Identifier">IRI</acronym>-to-<acronym title="Uniform Resource Identifier">URI</acronym> mapping [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>].</p>
-</div>
-
-
-<div id="graph-isomorphism" typeof="bibo:Chapter" resource="#graph-isomorphism" rel="bibo:chapter" class="section">
- <h3><span class="secno">3.6 </span>Graph Isomorphism</h3>
-
- <p id="section-graph-equality">Two
- <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a> <var>G</var> and <var>G'</var> are
- <dfn title="graph isomorphism" id="dfn-graph-isomorphism">isomorphic</dfn> if there
- is a bijection <var>M</var> between the sets of nodes of the two graphs,
- such that:</p>
-
- <ol>
- <li><var>M</var> maps blank nodes to blank nodes.</li>
- <li><var>M(lit)=lit</var> for all <a title="literal" href="#dfn-literal" class="internalDFN">RDF literals</a> <var>lit</var> which
- are nodes of <var>G</var>.</li>
-
- <li><var>M(uri)=uri</var> for all <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> <var>uri</var>
- which are nodes of <var>G</var>.</li>
-
- <li>The triple <var>( s, p, o )</var> is in <var>G</var> if and
- only if the triple <var>( M(s), p, M(o) )</var> is in
- <var>G'</var></li>
- </ol>
-
- <p>See also: <a href="#dfn-iri-equality" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym> equality</a>, <a href="#dfn-literal-equality" class="internalDFN">literal equality</a>.</p>
-
- <p>With this definition, <var>M</var> shows how each blank node
- in <var>G</var> can be replaced with
- a new blank node to give <var>G'</var>. Graph isomorphism
- is needed to support the RDF Test Cases [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-TESTCASES">RDF-TESTCASES</a></cite>] specification.</p>
-</div>
-
-</div>
-
-
-<div id="section-dataset" typeof="bibo:Chapter" resource="#section-dataset" rel="bibo:chapter" class="section">
- <h2><span class="secno">4 </span>RDF Datasets</h2>
-
- <p>An <dfn id="dfn-rdf-dataset">RDF Dataset</dfn> is a collection of
- <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>, and comprises:</p>
-
- <ul>
- <li>Exactly one <dfn id="dfn-default-graph">default graph</dfn>, being an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>.
- The default graph does not have a name and <em class="rfc2119" title="may">may</em> be empty.</li>
- <li>Zero or more <dfn title="named graph" id="dfn-named-graph">named graphs</dfn>.
- Each named graph is a pair consisting of an <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>
- (the <dfn id="dfn-graph-name">graph name</dfn>), and an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>.
- Graph names are unique within an RDF dataset.</li>
- </ul>
-
- <p><a title="blank node" href="#dfn-blank-node" class="internalDFN">Blank nodes</a> <em class="rfc2119" title="may">may</em> be shared between graphs
- in an <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>.</p>
-
- <div class="note" id="note-datasets">
- <p>Despite the use of the word “name”
- in “<a href="#dfn-named-graph" class="internalDFN">named graph</a>”, the <a href="#dfn-graph-name" class="internalDFN">graph name</a> does not formally
- <a href="#dfn-denote" class="internalDFN">denote</a> the graph. It is merely syntactically paired with
- the graph. RDF does not place any formal restrictions on what
- <a href="#dfn-resource" class="internalDFN">resource</a> the graph name may denote, nor on the relationship between
- that resource and the graph.</p>
-
- <p>Some <a href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>
- implementations do not track empty <a title="named graph" href="#dfn-named-graph" class="internalDFN">named graphs</a>.
- Applications can avoid interoperability issues by not
- ascribing importance to the presence or absence of empty named graphs.</p>
- </div>
-
- <p class="issue">Should RDF Concepts define any operations on RDF datasets,
- such as merge, union, isomorphism, equality, equivalence? Is anything
- needed to support the TriG test cases, SPARQL, etc.? This is
- <a href="https://www.w3.org/2011/rdf-wg/track/issues/111">ISSUE-111</a>.</p>
-</div>
-
-
-<div id="section-Datatypes" typeof="bibo:Chapter" resource="#section-Datatypes" rel="bibo:chapter" class="section">
- <h2><span class="secno">5 </span>Datatypes</h2>
-
- <p>Datatypes are used with RDF <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>
- to represent values such as strings, numbers and dates.
- The datatype abstraction used in RDF is compatible with XML Schema
- [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>]. Any datatype definition that conforms
- to this abstraction <em class="rfc2119" title="may">may</em> be used in RDF, even if not defined
- in terms of XML Schema. RDF re-uses many of the XML Schema
- built-in datatypes,
- and provides two additional built-in datatypes,
- <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code> and <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code>.
- The list of datatypes supported by an implementation is determined
- by its <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>.</p>
-
- <p>A <dfn id="dfn-datatype">datatype</dfn> consists of a <a href="#dfn-lexical-space" class="internalDFN">lexical space</a>,
- a <a href="#dfn-value-space" class="internalDFN">value space</a> and a <a href="#dfn-lexical-to-value-mapping" class="internalDFN">lexical-to-value mapping</a>, and
- is denoted by one or more <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>.</p>
-
-<p>The <dfn id="dfn-lexical-space">lexical space</dfn> of a datatype is a set of Unicode [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] strings.</p>
-
- <p>The <dfn id="dfn-lexical-to-value-mapping">lexical-to-value mapping</dfn> of a datatype is a set of
- pairs whose first element belongs to the <a href="#dfn-lexical-space" class="internalDFN">lexical space</a>,
- and the second element belongs to the <dfn id="dfn-value-space">value space</dfn>
- of the datatype. Each member of the lexical space is paired with exactly
- one value, and is a <em>lexical representation</em>
- of that value. The mapping can be seen as a function
- from the lexical space to the value space.</p>
-
- <p class="note"><a title="language-tagged string" href="#dfn-language-tagged-string" class="internalDFN">Language-tagged
- strings</a> have the <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a>
- <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#langString</code>.
- No datatype is formally defined for this <acronym title="Internationalized Resource Identifier">IRI</acronym> because the definition
- of <a title="datatype" href="#dfn-datatype" class="internalDFN">datatypes</a> does not accommodate
- <a title="language tag" href="#dfn-language-tag" class="internalDFN">language tags</a> in the <a href="#dfn-lexical-space" class="internalDFN">lexical space</a>.
- The <a href="#dfn-value-space" class="internalDFN">value space</a> associated with this datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> is the set
- of all pairs of strings and language tags.</p>
-
- <p>For example, the XML Schema datatype <code>xsd:boolean</code>,
- where each member of the <a href="#dfn-value-space" class="internalDFN">value space</a> has two lexical
- representations, is defined as follows:</p>
-
- <dl>
- <dt>Lexical space:</dt>
- <dd>{“<code>true</code>”, “<code>false</code>”, “<code>1</code>”, “<code>0</code>”}</dd>
- <dt>Value space:</dt>
- <dd>{<em><strong>true</strong></em>, <em><strong>false</strong></em>}</dd>
- <dt>Lexical-to-value mapping</dt>
- <dd>{
- <“<code>true</code>”, <em><strong>true</strong></em>>,
- <“<code>false</code>”, <em><strong>false</strong></em>>,
- <“<code>1</code>”, <em><strong>true</strong></em>>,
- <“<code>0</code>”, <em><strong>false</strong></em>>,
- }</dd>
- </dl>
-
- <p>The <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> that can be defined using this
- datatype are:</p>
-
- <table rules="all" summary="This table lists the literals of type xsd:boolean.">
- <tbody><tr>
- <th>Literal</th>
- <th>Value</th>
- </tr>
- <tr>
- <td align="center"><“<code>true</code>”, <code>xsd:boolean</code>></td>
- <td align="center"><em><strong>true</strong></em></td>
- </tr>
- <tr>
- <td align="center"><“<code>false</code>”, <code>xsd:boolean</code>></td>
- <td align="center"><em><strong>false</strong></em></td>
- </tr>
- <tr>
- <td align="center"><“<code>1</code>”, <code>xsd:boolean</code>></td>
- <td align="center"><em><strong>true</strong></em></td>
- </tr>
- <tr>
- <td align="center"><“<code>0</code>”, <code>xsd:boolean</code>></td>
- <td align="center"><em><strong>false</strong></em></td>
- </tr>
- </tbody></table>
-
-
-<div id="xsd-datatypes" typeof="bibo:Chapter" resource="#xsd-datatypes" rel="bibo:chapter" class="section">
- <h3><span class="secno">5.1 </span>The XML Schema Built-in Datatypes</h3>
-
- <p><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> of the form
- <code>http://www.w3.org/2001/XMLSchema#<em>xxx</em></code>,
- where <code><em>xxx</em></code>
- is the name of a datatype, denote the built-in datatypes defined in
- <em><a href="http://www.w3.org/TR/xmlschema11-2/">XML Schema 1.1 Part 2:
- Datatypes</a></em> [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>]. The XML Schema built-in types
- listed in the following table are the
- <dfn id="dfn-rdf-compatible-xsd-types">RDF-compatible XSD types</dfn>. Their use is <em class="rfc2119" title="recommended">recommended</em>.</p>
-
- <table rules="all" summary="A list of the RDF-compatible XSD types, with short descriptions">
- <tbody><tr><th></th><th>Datatype</th><th>Value space (informative)</th></tr>
-
- <tr><th rowspan="4">Core types</th><td><a href="http://www.w3.org/TR/xmlschema11-2/#string"><code>xsd:string</code></a></td><td>Character strings</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#boolean"><code>xsd:boolean</code></a></td><td>true, false</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#decimal"><code>xsd:decimal</code></a></td><td>Arbitrary-precision decimal numbers</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#integer"><code>xsd:integer</code></a></td><td>Arbitrary-size integer numbers</td></tr>
-
- <tr><th rowspan="2">IEEE floating-point<br />numbers</th>
- <td><a href="http://www.w3.org/TR/xmlschema11-2/#double"><code>xsd:double</code></a></td><td>64-bit floating point numbers incl. ±Inf, ±0, NaN</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#float"><code>xsd:float</code></a></td><td>32-bit floating point numbers incl. ±Inf, ±0, NaN</td></tr>
-
- <tr><th rowspan="4">Time and date</th>
- <td><a href="http://www.w3.org/TR/xmlschema11-2/#date"><code>xsd:date</code></a></td><td>Dates (yyyy-mm-dd) with or without timezone</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#time"><code>xsd:time</code></a></td><td>Times (hh:mm:ss.sss…) with or without timezone</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#dateTime"><code>xsd:dateTime</code></a></td><td>Date and time with or without timezone</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#dateTimeStamp"><code>xsd:dateTimeStamp</code></a></td><td>Date and time with required timezone</td></tr>
-
- <tr><th rowspan="8">Recurring and<br />partial dates</th>
- <td><a href="http://www.w3.org/TR/xmlschema11-2/#gYear"><code>xsd:gYear</code></a></td><td>Gregorian calendar year</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gMonth"><code>xsd:gMonth</code></a></td><td>Gregorian calendar month</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gDay"><code>xsd:gDay</code></a></td><td>Gregorian calendar day of the month</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gYearMonth"><code>xsd:gYearMonth</code></a></td><td>Gregorian calendar year and month</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#gMonthDay"><code>xsd:gMonthDay</code></a></td><td>Gregorian calendar month and day</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#duration"><code>xsd:duration</code></a></td><td>Duration of time</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#yearMonthDuration"><code>xsd:yearMonthDuration</code></a></td><td>Duration of time (months and years only)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#dayTimeDuration"><code>xsd:dayTimeDuration</code></a></td><td>Duration of time (days, hours, minutes, seconds only)</td></tr>
-
- <tr><th rowspan="12">Limited-range<br />integer numbers</th>
- <td><a href="http://www.w3.org/TR/xmlschema11-2/#byte"><code>xsd:byte</code></a></td><td>-128…+127 (8 bit)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#short"><code>xsd:short</code></a></td><td>-32768…+32767 (16 bit)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#int"><code>xsd:int</code></a></td><td>-2147483648…+2147483647 (32 bit)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#long"><code>xsd:long</code></a></td><td>-9223372036854775808…+9223372036854775807 (64 bit)</td></tr>
-
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedByte"><code>xsd:unsignedByte</code></a></td><td>0…255 (8 bit)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedShort"><code>xsd:unsignedShort</code></a></td><td>0…65535 (16 bit)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedInt"><code>xsd:unsignedInt</code></a></td><td>0…4294967295 (32 bit)</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#unsignedLong"><code>xsd:unsignedLong</code></a></td><td>0…18446744073709551615 (64 bit)</td></tr>
-
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#positiveInteger"><code>xsd:positiveInteger</code></a></td><td>Integer numbers >0</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#nonNegativeInteger"><code>xsd:nonNegativeInteger</code></a></td><td>Integer numbers ≥0</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#negativeInteger"><code>xsd:negativeInteger</code></a></td><td>Integer numbers <0</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#nonPositiveInteger"><code>xsd:nonPositiveInteger</code></a></td><td>Integer numbers ≤0</td></tr>
-
- <tr><th rowspan="2">Encoded binary data</th>
- <td><a href="http://www.w3.org/TR/xmlschema11-2/#hexBinary"><code>xsd:hexBinary</code></a></td><td>Hex-encoded binary data</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#base64Binary"><code>xsd:base64Binary</code></a></td><td>Base64-encoded binary data</td></tr>
-
- <tr><th rowspan="7">Miscellaneous<br />XSD types</th>
- <td><a href="http://www.w3.org/TR/xmlschema11-2/#anyURI"><code>xsd:anyURI</code></a></td><td>Absolute or relative URIs and IRIs</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#language"><code>xsd:language</code></a></td><td>Language tags per [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>]</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#normalizedString"><code>xsd:normalizedString</code></a></td><td>Whitespace-normalized strings</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#token"><code>xsd:token</code></a></td><td>Tokenized strings</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#NMTOKEN"><code>xsd:NMTOKEN</code></a></td><td>XML NMTOKENs</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#Name"><code>xsd:Name</code></a></td><td>XML Names</td></tr>
- <tr><td><a href="http://www.w3.org/TR/xmlschema11-2/#NCName"><code>xsd:NCName</code></a></td><td>XML NCNames</td></tr>
- </tbody></table>
-
- <p>The other built-in XML Schema datatypes are unsuitable
- for various reasons, and <em class="rfc2119" title="should not">should not</em> be used.</p>
-
- <div class="note">
- <ul>
- <li><a href="http://www.w3.org/TR/xmlschema11-2/#QName"><code>xsd:QName</code></a>
- and
- <a href="http://www.w3.org/TR/xmlschema11-2/#ENTITY"><code>xsd:ENTITY</code></a>
- require an enclosing XML document context.</li>
- <li><a href="http://www.w3.org/TR/xmlschema11-2/#ID"><code>xsd:ID</code></a>
- and
- <a href="http://www.w3.org/TR/xmlschema11-2/#IDREF"><code>xsd:IDREF</code></a>
- are for cross references within an XML document.</li>
- <li><a href="http://www.w3.org/TR/xmlschema11-2/#NOTATION"><code>xsd:NOTATION</code></a>
- is not intended for direct use.</li>
- <li><a href="http://www.w3.org/TR/xmlschema11-2/#IDREFS"><code>xsd:IDREFS</code></a>,
- <a href="http://www.w3.org/TR/xmlschema11-2/#ENTITIES"><code>xsd:ENTITIES</code></a>
- and
- <a href="http://www.w3.org/TR/xmlschema11-2/#NMTOKENS"><code>xsd:NMTOKENS</code></a>
- are sequence-valued datatypes which do not fit the RDF <a href="#dfn-datatype" class="internalDFN">datatype</a>
- model.</li>
- </ul>
- </div>
-
-</div>
-
-
-<div id="section-html" typeof="bibo:Chapter" resource="#section-html" rel="bibo:chapter" class="section">
- <h3><span class="secno">5.2 </span>The <code>rdf:HTML</code> Datatype</h3>
-
- <p>RDF provides for HTML content as a possible <a href="#dfn-literal-value" class="internalDFN">literal value</a>.
- This allows markup in literal values. Such content is indicated
- in an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> using a <a href="#dfn-literal" class="internalDFN">literal</a> whose <a href="#dfn-datatype" class="internalDFN">datatype</a>
- is a special built-in datatype <code><dfn id="dfn-rdf-html">rdf:HTML</dfn></code>.
- This datatype is defined as follows:</p>
-
- <dl>
- <dt>An <acronym title="Internationalized Resource Identifier">IRI</acronym> denoting this datatype</dt>
- <dd>is <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#HTML</code>.</dd>
-
- <dt>The lexical space</dt>
- <dd>is the set of Unicode [<cite><a class="bibref" rel="biblioentry" href="#bib-UNICODE">UNICODE</a></cite>] strings.</dd>
-
- <dt>The value space</dt>
- <dd>is a set of DOM
- <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
- nodes [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>]. Two
- <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
- nodes <em>A</em> and <em>B</em> are considered equal if and only if
- the DOM method
- <code><em>A</em>.<a href="http://www.w3.org/TR/dom/#dom-node-isequalnode">isEqualNode</a>(<em>B</em>)</code>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>] returns <code>true</code>.</dd>
-
- <dt>The lexical-to-value mapping</dt>
- <dd>
- <p>Each member of the lexical space is associated with the result
- of applying the following algorithm:</p>
- <ul>
- <li>Let <code>domnodes</code> be the list of
- <a href="http://www.w3.org/TR/dom/#node">DOM nodes</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>]
- that result from applying the
- <a href="http://www.w3.org/TR/html5/the-end.html#parsing-html-fragments">HTML fragment parsing algorithm</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-HTML5">HTML5</a></cite>]
- to the input string, without a context element.</li>
- <li>Let <code>domfrag</code> be a DOM
- <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>] whose <code>childNodes</code> attribute is equal to
- <code>domnodes</code></li>
- <li>Return <code>domfrag.<a href="http://www.w3.org/TR/dom/#dom-node-normalize">normalize</a>()</code></li>
- </ul>
- </dd>
- </dl>
-
- <p class="note" id="note-html">
- Any language annotation (<code>lang="…"</code>) or
- XML namespaces (<code>xmlns</code>) desired in the HTML content
- must be included explicitly in the HTML literal. Relative URLs
- in attributes such as <code>href</code> do not have a well-defined
- base URL and are best avoided.
- RDF applications may use additional equivalence relations,
- such as that which relates an <code>xsd:string</code> with an
- <code>rdf:HTML</code> literal corresponding to a single text node
- of the same string.</p>
-</div>
-
-<div id="section-XMLLiteral" typeof="bibo:Chapter" resource="#section-XMLLiteral" rel="bibo:chapter" class="section">
- <h3><span class="secno">5.3 </span>The <code>rdf:XMLLiteral</code> Datatype</h3>
-
- <p>RDF provides for XML content as a possible <a href="#dfn-literal-value" class="internalDFN">literal value</a>.
- Such content is indicated in an <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> using a <a href="#dfn-literal" class="internalDFN">literal</a>
- whose <a href="#dfn-datatype" class="internalDFN">datatype</a> is a special built-in datatype
- <code><dfn id="dfn-rdf-xmlliteral">rdf:XMLLiteral</dfn></code>, which is defined as follows:</p>
-
- <dl>
- <dt id="XMLLiteral-uri">An <acronym title="Internationalized Resource Identifier">IRI</acronym> denoting
- this datatype</dt>
-
- <dd>is
- <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>.</dd>
-
- <dt id="XMLLiteral-lexical-space">The lexical space</dt>
-
- <dd>is the set of all strings which are well-balanced, self-contained
- <a href="http://www.w3.org/TR/2000/REC-xml-20001006#NT-content">XML content</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-XML10">XML10</a></cite>]; and for which embedding between an arbitrary
- XML start tag and an end tag yields a document conforming to
- <a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/">XML Namespaces</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-NAMES">XML-NAMES</a></cite>].</dd>
-
- <dt id="XMLLiteral-value-space">The value space</dt>
-
- <dd>is a set of DOM
- <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
- nodes [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>]. Two
- <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
- nodes <em>A</em> and <em>B</em> are considered equal
- if and only if the DOM method
- <code><em>A</em>.<a href="http://www.w3.org/TR/dom/#dom-node-isequalnode">isEqualNode</a>(<em>B</em>)</code>
- returns <code>true</code>.</dd>
-
- <dt id="XMLLiteral-mapping">The lexical-to-value mapping</dt>
-
- <dd>
- <p>Each member of the lexical space is associated with the result
- of applying the following algorithm:</p>
- <ul>
- <li>Let <code>domfrag</code> be a DOM
- <a href="http://www.w3.org/TR/dom/#interface-documentfragment"><code>DocumentFragment</code></a>
- node [<cite><a class="bibref" rel="biblioentry" href="#bib-DOM4">DOM4</a></cite>] corresponding to the input string</li>
- <li>Return <code>domfrag.<a href="http://www.w3.org/TR/dom/#dom-node-normalize">normalize</a>()</code></li>
- </ul></dd>
-
- <dt id="XMLLiteral-canonical">The canonical mapping</dt>
- <dd>defines a
- <a href="http://www.w3.org/TR/xmlschema11-2/#dt-canonical-mapping">canonical lexical form</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>] for each member of the value space.
- The <code>rdf:XMLLiteral</code> canonical mapping is the
- <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/#def-exclusive-XML-canonicalization-method">exclusive
- XML canonicalization method</a> (<em>with comments, with empty
- <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/#def-InclusiveNamespaces-PrefixList">
- InclusiveNamespaces PrefixList</a></em>) [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-EXC-C14N">XML-EXC-C14N</a></cite>].
-
- </dd></dl>
-
- <p class="note">Any XML namespace declarations (<code>xmlns</code>),
- language annotation (<code>xml:lang</code>) or base <acronym title="Uniform Resource Identifier">URI</acronym>
- declarations (<code>xml:base</code>) desired in the
- XML content must be included explicitly in the XML literal.
- Note that some concrete RDF syntaxes may define mechanisms
- for inheriting them from the context
- (e.g., <a href="http://www.w3.org/TR/rdf-syntax-grammar/#parseTypeLiteralPropertyElt"><code>@parseType="literal"</code></a>
- in RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>]).</p>
-</div>
-
-<div id="datatype-maps" typeof="bibo:Chapter" resource="#datatype-maps" rel="bibo:chapter" class="section">
- <h3><span class="secno">5.4 </span>Datatype Maps</h3>
-
- <p>A <dfn id="dfn-datatype-map">datatype map</dfn> is an implementation-defined set of
- <<a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>, <a href="#dfn-datatype" class="internalDFN">datatype</a>> pairs such that no
- <acronym title="Internationalized Resource Identifier">IRI</acronym> appears twice in the set.
- It can be seen as a function from IRIs to datatypes,
- where the IRIs denote the datatypes.</p>
-
- <p>If a <a href="#dfn-datatype-map" class="internalDFN">datatype map</a> contains the <acronym title="Internationalized Resource Identifier">IRI</acronym>
- <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>,
- then it <em class="rfc2119" title="must">must</em> be paired with the datatype
- <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code>.</p>
-
- <p>If a <a href="#dfn-datatype-map" class="internalDFN">datatype map</a> contains the <acronym title="Internationalized Resource Identifier">IRI</acronym>
- <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#HTML</code>,
- then it <em class="rfc2119" title="must">must</em> be paired with the datatype
- <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code>.</p>
-
- <p>If a <a href="#dfn-datatype-map" class="internalDFN">datatype map</a> contains an <acronym title="Internationalized Resource Identifier">IRI</acronym> of the form
- <code>http://www.w3.org/2001/XMLSchema#<em>xxx</em></code>,
- then it <em class="rfc2119" title="must">must</em> be paired with the
- <a title="RDF-compatible XSD types" href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD type</a>
- named <code>xsd:<em>xxx</em></code>.</p><p>
-
- </p><p>Other specifications
- <em class="rfc2119" title="may">may</em> impose additional constraints on the <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>,
- for example, require support for certain datatypes.</p>
-
- <p class="note" id="note-custom-datatypes">The Web Ontology Language
- [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>] offers facilities for formally defining
- <a href="http://www.w3.org/TR/owl2-syntax/#Datatype_Definitions">custom
- datatypes</a> that can be used with RDF. Furthermore, a practice for
- identifying
- <a href="http://www.w3.org/TR/swbp-xsch-datatypes/#sec-userDefined">
- user-defined simple XML Schema datatypes</a>
- is suggested in [<cite><a class="bibref" rel="biblioentry" href="#bib-SWBP-XSCH-DATATYPES">SWBP-XSCH-DATATYPES</a></cite>]. RDF implementations
- are not required to support either of these facilities.</p>
-</div>
-
-
-<div id="section-Literal-Value" typeof="bibo:Chapter" resource="#section-Literal-Value" rel="bibo:chapter" class="section">
- <h3><span class="secno">5.5 </span>The Value Corresponding to a Literal</h3>
-
- <p>The <dfn id="dfn-literal-value">literal value</dfn> associated with a <a href="#dfn-literal" class="internalDFN">literal</a> is:</p>
-
- <ol>
- <li><strong>If the literal is a <a href="#dfn-language-tagged-string" class="internalDFN">language-tagged string</a>,</strong>
- then the literal value is a pair consisting of its <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>
- and its <a href="#dfn-language-tag" class="internalDFN">language tag</a>, in that order.</li>
- <li><strong>If the literal's <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a> is not in the
- implementation-defined <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>,</strong> then the literal value
- is not defined by this specification.</li>
- <li>Let <em>d</em> be the <a href="#dfn-datatype" class="internalDFN">datatype</a> associated with the
- datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> in the implementation-defined datatype map.</li>
- <li><strong>If the literal's <a href="#dfn-lexical-form" class="internalDFN">lexical form</a> is in the
- <a href="#dfn-lexical-space" class="internalDFN">lexical space</a> of <em>d</em>,</strong> then the literal value
- is the result of applying the <a href="#dfn-lexical-to-value-mapping" class="internalDFN">lexical-to-value mapping</a>
- of <em>d</em> to the <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>.</li>
- <li><strong>Otherwise,</strong> the literal is
- <dfn id="dfn-ill-typed">ill-typed</dfn>, and no literal value can be
- associated with the literal. Such a case, while in error, is not
- <em>syntactically</em> ill-formed.</li>
- </ol>
-
- <p class="issue">What does it mean when a literal is ill-typed or when something is not in the datatype map? What should an implementation do? Should authors avoid generating such graphs? Should consumers reject it? Is an implementation that rejects ill-formed xsd:dates conforming? Why is an ill-typed literal not necessarily an inconsistency? This is <a href="https://www.w3.org/2011/rdf-wg/track/issues/109">ISSUE-109</a>.</p>
-</div>
-
-
-</div>
-
-
-<div id="section-fragID" class="informative section" typeof="bibo:Chapter" resource="#section-fragID" rel="bibo:chapter">
- <h2><span class="secno">6 </span>Fragment Identifiers</h2><p><em>This section is non-normative.</em></p>
-
- <p class="issue">This section addresses the use of fragment IRIs
- in concrete syntaxes for <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>, but not
- for <a title="RDF dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a>. Going beyond the questions
- of pure fragment identifiers, the introduction of RDF datasets raises
- additional questions related to content negotiation and the
- authoritativeness of representations. For example, is it legitimate
- to content-negotiate between an RDF graph representation and an
- RDF dataset representation that only contains a default graph?
- Are the contents of graphs named <code><#xxx></code> an
- authoritative representation of whatever is identified by
- <code><#xxx></code>? This is
- <a href="https://www.w3.org/2011/rdf-wg/track/issues/105">ISSUE-105</a>.</p>
-
- <p>RDF uses <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, which may include
- <dfn id="dfn-fragment-identifiers">fragment identifiers</dfn>, as resource identifiers.
- The semantics of fragment identifiers is
- <a href="http://tools.ietf.org/html/rfc3986#section-3.5">defined in
- RFC 3986</a> [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>]: They identify a secondary resource
- that is usually a part of, view of, defined in, or described in
- the primary resource, and the precise semantics depend on the set
- of representations that might result from a retrieval action
- on the primary resource.</p>
-
- <p>This section discusses the handling of fragment identifiers
- in representations that encode <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>.</p>
-
- <p>In RDF-bearing representations of a primary resource
- <code><foo></code>,
- the secondary resource identified by a fragment <code>bar</code>
- is the <a href="#dfn-resource" class="internalDFN">resource</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by the
- full <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> <code><foo#bar></code> in the <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>.
- Since IRIs in RDF graphs can denote anything, this can be
- something external to the representation, or even external
- to the web.</p>
-
- <p>In this way, the RDF-bearing representation acts as an intermediary
- between the web-accessible primary resource, and some set of possibly
- non-web or abstract entities that the <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> may describe.</p>
-
- <p>In cases where other specifications constrain the semantics of
- fragment identifiers in RDF-bearing representations, the encoded
- <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a> should use fragment identifiers in a way that is consistent
- with these constraints. For example, in an HTML+RDFa document [<cite><a class="bibref" rel="biblioentry" href="#bib-HTML-RDFA">HTML-RDFA</a></cite>],
- the fragment <code>chapter1</code> may identify a document section
- via the semantics of HTML's <code>@name</code> or <code>@id</code>
- attributes. The <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a> <code><#chapter1></code> should
- then be taken to <a href="#dfn-denote" class="internalDFN">denote</a> that same section in any RDFa-encoded
- <a title="RDF triple" href="#dfn-rdf-triple" class="internalDFN">triples</a> within the same document.
- Similarly, if the <code>@xml:id</code> attribute [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-ID">XML-ID</a></cite>] is used
- in an RDF/XML document, then the corresponding <acronym title="Internationalized Resource Identifier">IRI</acronym>
- should be taken to denote an XML element.</p>
-
- <p>Primary resources may have multiple representations that are
- made available via
- <a href="http://www.w3.org/TR/webarch/#frag-coneg">content negotiation</a>
- [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>]. Fragments in RDF-bearing representations
- should be used in a way that is consistent with the semantics imposed by any
- non-RDF representations. For example, if the fragment
- <code>chapter1</code> identifies a document section in an
- HTML representation of the primary resource, then the <a href="#dfn-iri" class="internalDFN"><acronym title="Internationalized Resource Identifier">IRI</acronym></a>
- <code><#chapter1></code>
- should be taken to <a href="#dfn-denote" class="internalDFN">denote</a> that same section in all RDF-bearing
- representations of the same primary resource.</p>
-</div>
-
-
-<div id="section-Acknowledgments" class="informative section" typeof="bibo:Chapter" resource="#section-Acknowledgments" rel="bibo:chapter">
- <h2><span class="secno">7 </span>Acknowledgments</h2><p><em>This section is non-normative.</em></p>
-
- <p>The RDF 1.1 editors acknowledge valuable contributions from
- Thomas Baker, Dan Brickley, Gavin Carothers, Jeremy Carroll,
- Pierre-Antoine Champin, Dan Connolly,
- John Cowan, Martin J. Dürst, Alex Hall, Steve Harris, Pat Hayes,
- Ivan Herman, Peter F. Patel-Schneider, Addison Phillips,
- Eric Prud'hommeaux, Andy Seaborne, Leif Halvard Silli,
- Nathan Rixham, Dominik Tomaszuk and Antoine Zimmermann.</p>
-
- <p>The RDF 2004 editors acknowledge valuable contributions from
- Frank Manola, Pat Hayes, Dan Brickley, Jos de Roo, Sergey Melnik,
- Dave Beckett, Patrick Stickler, Peter F. Patel-Schneider, Jerome Euzenat,
- Massimo Marchiori, Tim Berners-Lee, Dave Reynolds and Dan Connolly.</p>
-
- <p>This specification is a product of extended deliberations by the
- <a href="http://www.w3.org/2000/09/dbwg/details?group=46168&public=1">members of the RDF Working Group</a>.
- It draws upon two earlier specifications,
- <em><a href="http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/">RDF Model and Syntax</a></em>, edited by Ora Lassilla and Ralph Swick,
- and <em><a href="http://www.w3.org/TR/2000/CR-rdf-schema-20000327/">RDF Schema</a></em>, edited by Dan Brickley and R. V. Guha, which were produced by
- <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#section-Acknowledgments">members
- of the RDFcore and Schema Working Groups</a>.</p>
-</div>
-
-
-<div class="appendix informative section" id="changes" typeof="bibo:Chapter" resource="#changes" rel="bibo:chapter">
- <h2><span class="secno">A </span>Changes between RDF 2004 and RDF 1.1</h2><p><em>This section is non-normative.</em></p>
-
- <p class="issue">The Working Group intends to publish a separate
- Working Group Note entitled
- <em>RDF 1.1 New Features and Migration Guide</em>. This is
- <a href="http://www.w3.org/2011/rdf-wg/track/actions/193">ACTION-193</a>.
- Some or all material in this section may be moved to that document. In the
- meantime, the <a href="#change-log">Change Log</a> is a good indication
- as to what else has changed and why.</p>
-
- <p>This section discusses changes between the
- <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/">2004
- Recommendation of <em>RDF Concepts and Abstract Syntax</em></a> and
- the RDF 1.1 versions of this specification.</p>
-
- <p>Previous versions of RDF used the term
- “<dfn id="dfn-rdf-uri-reference">RDF <acronym title="Uniform Resource Identifier">URI</acronym> Reference</dfn>” instead of “<acronym title="Internationalized Resource Identifier">IRI</acronym>” and allowed
- additional characters:
- “<code><</code>”, “<code>></code>”,
- “<code>{</code>”, “<code>}</code>”,
- “<code>|</code>”, “<code>\</code>”,
- “<code>^</code>”, “<code>`</code>”,
- ‘<code>“</code>’ (double quote), and “<code> </code>” (space).
- In IRIs, these characters must be percent-encoded as
- described in <a href="http://tools.ietf.org/html/rfc3986#section-2.1">section 2.1</a>
- of [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>].</p>
-
- <p>In earlier versions of RDF, <a title="literal" href="#dfn-literal" class="internalDFN">literals</a>
- with a <a href="#dfn-language-tag" class="internalDFN">language tag</a> did not have a <a href="#dfn-datatype-iri" class="internalDFN">datatype <acronym title="Internationalized Resource Identifier">IRI</acronym></a>, and
- <a title="simple literal" href="#dfn-simple-literal" class="internalDFN">simple literals</a> could appear
- directly in the abstract syntax. Simple literals and literals with a
- language tag were collectively known as
- <dfn title="plain literal" id="dfn-plain-literal">plain literals</dfn>.</p>
-
- <p>Earlier versions of RDF permitted
- <a title="language tag" href="#dfn-language-tag" class="internalDFN">language tags</a> that
- adhered to the generic tag/subtag syntax of language tags,
- but were not well-formed according to [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>]. Such
- language tags do not conform to RDF 1.1.</p>
-
- <p>The <code>xsd:string</code> datatype does not
- permit the <code>#x0</code> character, and implementations may not permit
- control codes in the <code>#x1-#x1F</code> range. Earlier versions of
- RDF allowed these characters in
- <a title="simple literal" href="#dfn-simple-literal" class="internalDFN">simple literals</a>, although they
- could never be serialized in a <acronym title="World Wide Web Consortium">W3C</acronym>-recommended concrete syntax.</p>
-</div>
-
-
-<div class="appendix informative section" id="change-log" typeof="bibo:Chapter" resource="#change-log" rel="bibo:chapter">
- <h2><span class="secno">B </span>Change Log</h2><p><em>This section is non-normative.</em></p>
-
-
-<div class="appendix section" id="changes-wd3" typeof="bibo:Chapter" resource="#changes-wd3" rel="bibo:chapter">
- <h3><span class="secno">B.1 </span>Changes from 05 June 2012 WD to this version</h3>
-
- <p>This section lists changes from the
- <a href="http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/">05 June 2012 Working Draft (WD)</a> to this Working Draft of
- <em>RDF 1.1 Concepts and Abstract Syntax</em>.</p>
-
- <ul>
- <li>2013-01-14: Editorial changes in response to <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Nov/0354.html">reviews from Antoine Zimmermann</a> <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Nov/0360.html">and Peter Patel-Schneider</a></li>
- <li>2012-11-21: Replaced the placeholder term “g-box” with “<a href="#dfn-rdf-source" class="internalDFN">RDF source</a>” (<a href="https://www.w3.org/2011/rdf-wg/track/issues/110">ISSUE-110</a>)</li>
- <li>2012-11-21: Removed various Notes (as <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Nov/0131.html">listed here</a>), and refactored others (<a href="https://www.w3.org/2011/rdf-wg/track/issues/104">ISSUE-104</a>)</li>
- <li>2012-11-17: Many changes to Introduction, including mostly new subsections on <a href="#managing-graphs">Working with Multiple RDF Graphs and G-Boxes</a>, <a href="#entailment">Equivalence, Entailment and Inconsistencies</a>, and <a href="#rdf-documents">RDF Documents and Syntaxes</a></li>
- <li>2012-11-17: Reverted section on <a href="#section-blank-nodes">Blank Nodes</a> to earlier state</li>
- <li>2012-11-17: Changes, mostly but not exclusively editorial, to section on <a href="#section-fragID">Fragment Identifiers</a></li>
- <li>2012-11-13: Remove the notion of other specs conforming to this spec from the <a href="#conformance">Conformance</a> section. This spec simply provides definitions that other specs can use.</li>
- <li>2012-11-09: Updated the <a href="#section-dataset">section on RDF datasets</a> to reflect <a href="http://www.w3.org/2011/rdf-wg/meeting/2012-10-29">various WG resolutions</a> around named graphs</li>
- <li>2012-11-09: Re-wrote the <a href="#section-blank-nodes">section on Blank Nodes</a>, including a definition of “fresh blank nodes” and an extended Note on standardizing apart blank node IDs</li>
- <li>2012-11-09: Moved all informative material about changes between RDF 2004 and RDF 1.1 to a <a href="#changes">new appendix</a></li>
- <li>2012-11-07: Add <a href="#change-over-time">new informative section on Change Over Time</a></li>
- <li>2012-11-07: New <a href="#abstract">abstract</a>, based on comments from Dan Connolly</li>
- <li>2012-11-06: Tweak definition of <a title="literal" href="#dfn-literal" class="internalDFN">literals</a> to avoid apparent contradiction (<a href="http://www.w3.org/2011/rdf-wg/track/issues/94">ISSUE-94</a>)</li>
- <li>2012-11-06: Add a <a href="#note-custom-datatypes">note</a> on the use of OWL2 custom datatypes and simple user-defined XML Schema datatypes (<a href="http://www.w3.org/2011/rdf-wg/track/issues/96">ISSUE-96</a>)</li>
- <li>2012-11-06: Add a <a href="#note-empty-named-graphs">note on empty named graphs</a> (<a href="http://www.w3.org/2011/rdf-wg/track/issues/22">ISSUE-22</a>)</li>
- <li>2012-11-06: Modify the <a title="relative IRI" href="#dfn-relative-iri" class="internalDFN">Note on relative IRIs</a> to stress their usefulness and to clarify the role of RFC 3986 in the resolution process</li>
- <li>2012-11-06: Informatively <a href="#referents">explain</a> that IRIs in this spec are treated only as nodes in a graph data model, and no interaction model is implied</li>
- <li>2012-08-09: Clarify that all datatypes are optional, but RDF-conformant specifications <em class="rfc2119" title="may">may</em> require specific <a title="datatype map" href="#dfn-datatype-map" class="internalDFN">datatype maps</a></li>
- </ul>
-</div>
-
-
-<div class="appendix section" id="changes-wd2" typeof="bibo:Chapter" resource="#changes-wd2" rel="bibo:chapter">
- <h3><span class="secno">B.2 </span>Changes from FPWD to 05 June 2012 WD</h3>
-
- <p>This section lists changes from the
- <a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">First Public Working Draft (FPWD)</a>
- to the <a href="http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/">05 June 2012 Working Draft (WD)</a> of
- <em>RDF 1.1 Concepts and Abstract Syntax</em>.</p>
-
- <ul>
- <li>2012-05-31: Update <a href="#section-Acknowledgments">Acknowledgements</a> for RDF 1.1; added RDFa 1.1 markup</li>
- <li>2012-05-24: Moved the multigraph section to an earlier position and renamed it to “<a href="#section-dataset">RDF Datasets</a>”</li>
- <li>2012-05-17: Changed normative reference for DOM in <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code> from [DOM3CORE] to [DOM4] as we need DOM4 anyways for <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code></li>
- <li>2012-05-17: Added <code><a href="#dfn-rdf-html" class="internalDFN">rdf:HTML</a></code> datatype (<a href="http://www.w3.org/2011/rdf-wg/track/issues/63">ISSUE-63</a>)</li>
- <li>2012-05-17: Added <a href="http://www.w3.org/TR/xmlschema11-2/#duration"><code>xsd:duration</code></a> to list of <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a> (<a href="http://www.w3.org/2011/rdf-wg/track/issues/88">ISSUE-88</a>)</li>
- <li>2012-05-14: Replaced the example graph diagram in <a href="#data-model">Section 1.1</a> with a re-drawn SVG version, with support from Dominik Tomaszuk</li>
- <li>2012-05-10: New <a href="#conformance">Conformance section</a> to explain that this specification is not implemented directly, but through other specifications that use our definitions</li>
- <li>2012-05-10: Simplified <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code>'s new value space slightly after feedback from Ivan Herman and Arnaud Le Hors.</li>
- <li>2012-05-10: Added an informative subsection on <a href="#vocabularies">RDF vocabularies and namespace IRIs</a>.</li>
- <li>2012-05-09: Removed an example from the conformance section that didn't make sense any more with the modified <code>rdf:XMLLiteral</code>. Added some new issue boxes.</li>
- <li>2012-05-09: <code><a href="#dfn-rdf-xmlliteral" class="internalDFN">rdf:XMLLiteral</a></code> no longer requires lexical forms to be canonicalized, and the value space is now defined in terms of [DOM-LEVEL-3-CORE] (<a href="https://www.w3.org/2011/rdf-wg/track/issues/13">ISSUE-13</a>)</li>
- <li>2012-05-09: Removed Section 3 <em>RDF Vocabulary <acronym title="Internationalized Resource Identifier">IRI</acronym> and Namespace</em>; its contents will be folded into the RDF Schema document</li>
- <li>2012-05-02: Renamed “graph equivalence” to “<a href="#dfn-graph-isomorphism" class="internalDFN">graph isomorphism</a>” (<a href="https://www.w3.org/2011/rdf-wg/track/issues/86">ISSUE-86</a>)</li>
- <li>2012-05-02: Updated [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-1">XMLSCHEMA11-1</a></cite>] and [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">XMLSCHEMA11-2</a></cite>] references to the new REC versions</li>
- <li>2012-05-02: Added the new XSD 1.1 datatypes <a href="http://www.w3.org/TR/xmlschema11-2/#dayTimeDuration">xsd:dayTimeDuration</a>, <a href="http://www.w3.org/TR/xmlschema11-2/#yearMonthDuration">xsd:yearMonthDuration</a> and <a href="http://www.w3.org/TR/xmlschema11-2/#dateTimeStamp">xsd:dateTimeStamp</a> to the list of <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a> (<a href="https://www.w3.org/2011/rdf-wg/track/issues/66">ISSUE-66</a>)</li>
- <li>2012-04-26: Remove normative definition of “property” as it disagreed with RDF Semantics; small editorial changes.</li>
- <li>2011-11-21: Updated XHTML 1.0 reference to XHTML 1.1</li>
- <li>2011-11-20: Added table of <a href="#dfn-rdf-compatible-xsd-types" class="internalDFN">RDF-compatible XSD types</a>, and definition of <a href="#dfn-datatype-map" class="internalDFN">datatype map</a>, both adapted from previous content in [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>]
- </li><li>2011-11-18: Replaced informative <em>Introduction</em> and <em>RDF Concepts</em> sections with a new extended introduction. Folded some content from <em>RDF Concepts</em> into the later normative sections, mostly as examples and notes.</li>
- <li>2011-11-10: Changed XSD references to version 1.1</li>
- <li>2011-11-10: Replaced the <a href="#section-fragID">section on fragment identifiers</a> with an updated account that follows RFC 3986</li>
- <li>2011-11-09: Updated the two sections on literals to reflect the <a href="http://www.w3.org/2011/rdf-wg/track/issues/71">ISSUE-71</a> resolution that literals with language tag now have the datatype <acronym title="Internationalized Resource Identifier">IRI</acronym> <code>rdf:langString</code>. Formally introduced the term “language-tagged string”.</li>
- <li>2011-11-09: Add a note that explains that #x0-#x1F are no longer allowed in simple literals
- </li></ul>
-</div>
-
-<div class="appendix section" id="changes-fpwd" typeof="bibo:Chapter" resource="#changes-fpwd" rel="bibo:chapter">
- <h3><span class="secno">B.3 </span>Changes from RDF 2004 to FPWD</h3>
-
- <p>This section lists changes from the
- <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/">2004 Recommendation of
- <em>RDF Concepts and Abstract Syntax</em></a> to the
- <a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">First Public Working Draft (FPWD) of
- <em>RDF 1.1 Concepts and Abstract Syntax</em></a>.</p>
-
- <ul>
- <li>2011-08-13: Updated Turtle reference to Turtle FPWD</li>
- <li>2011-07-21: Condensed the 2004 acknowledgements</li>
- <li>2011-07-21: Updated the two sections on literals to reflect the <a href="http://www.w3.org/2011/rdf-wg/track/issues/12">ISSUE-12</a> resolution that simple literals are no longer part of the abstract syntax. Formally introduced the terms “language-tagged literal”, “simple literal”.</li>
- <li>2011-07-21: Updated the introduction, and removed many mentions of RDF/XML. Changed the normative reference for the terms in the RDF namespace from the RDF/XML spec to the RDF Schema spec. Removed any mention of the 1999 version of RDF.</li>
- <li>2011-07-21: Replaced RFC 2279 reference (UTF-8) with RFC 3629</li>
- <li>2011-07-20: Removed informative sections “Motivations and Goals” (see <a href="http://www.w3.org/TR/rdf-concepts/#section-Overview">RDF 2004 version</a>) and “RDF Expression of Simple Facts” (see <a href="http://www.w3.org/TR/rdf-concepts/#section-SimpleFacts">RDF 2004 version</a>)</li>
- <li>2011-06-01: Replaced the <acronym title="Uniform Resource Identifier">URI</acronym> References section with <a href="#section-IRIs">new section on IRIs</a>, and changed “RDF <acronym title="Uniform Resource Identifier">URI</acronym> Reference” to “<acronym title="Internationalized Resource Identifier">IRI</acronym>” throughout the document.</li>
- <li>2011-06-01: Changed language tag definition to require well-formedness according to BCP47; added a note that this invalidates some RDF</li>
- <li>2011-05-25: Added boxes for known WG issues throught the document</li>
- <li>2011-05-25: Deleted “Structure of this Document” section, it added no value beyond the TOC</li>
- <li>2011-05-25: Implemented resolution of <a href="http://www.w3.org/2011/rdf-wg/track/issues/40">ISSUE-40: Skolemization advice in the RDF dcocument</a> by adding a section on <a href="#section-skolemization">Replacing Blank Nodes with IRIs</a></li>
- <li>2011-05-25: rdf:XMLLiteral is disjoint from any datatype not explicitly related to it, per erratum <a href="http://www.w3.org/2001/sw/RDFCore/errata#concept-xmlliteral">[concept-xmlliteral]</a></li>
- <li>2011-05-25: Added Conformance section with RFC2119 reference</li>
- <li>2011-05-25: Updated all <acronym title="World Wide Web Consortium">W3C</acronym> references to latest editions, and Unicode from v3 to v4</li>
- <li>2011-05-24: Converted to ReSpec, changed metadata to reflect RDF 1.1</li>
- </ul>
-</div>
-
-</div>
-
-
-
-
-<div id="references" class="appendix section" typeof="bibo:Chapter" resource="#references" rel="bibo:chapter"><h2><span class="secno">C </span>References</h2><div id="normative-references" typeof="bibo:Chapter" resource="#normative-references" rel="bibo:chapter" class="section"><h3><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography" about=""><dt id="bib-BCP47">[BCP47]</dt><dd rel="dcterms:requires">A. Phillips; M. Davis. <a href="http://tools.ietf.org/html/bcp47"><cite>Tags for Identifying Languages</cite></a> September 2009. IETF Best Current Practice. URL: <a href="http://tools.ietf.org/html/bcp47">http://tools.ietf.org/html/bcp47</a>
-</dd><dt id="bib-DOM4">[DOM4]</dt><dd rel="dcterms:requires">Anne van Kesteren; Aryeh Gregor; Ms2ger. <a href="http://www.w3.org/TR/2012/WD-dom-20120405/"><cite>DOM4.</cite></a> 5 April 2012. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2012/WD-dom-20120405/">http://www.w3.org/TR/2012/WD-dom-20120405/</a>
-</dd><dt id="bib-HTML5">[HTML5]</dt><dd rel="dcterms:requires">Ian Hickson; David Hyatt. <a href="http://www.w3.org/TR/html5"><cite>HTML5.</cite></a> 25 October 2012. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2012/WD-html5-20121025/">http://www.w3.org/TR/2012/WD-html5-20121025/</a>
-</dd><dt id="bib-NFC">[NFC]</dt><dd rel="dcterms:requires">M. Davis, Ken Whistler. <a href="http://www.unicode.org/reports/tr15/"><cite>TR15, Unicode Normalization Forms.</cite></a>. 17 September 2010, URL: <a href="http://www.unicode.org/reports/tr15/">http://www.unicode.org/reports/tr15/</a>
-</dd><dt id="bib-RFC2119">[RFC2119]</dt><dd rel="dcterms:requires">S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate Requirement Levels.</cite></a> March 1997. Internet RFC 2119. URL: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
-</dd><dt id="bib-RFC3987">[RFC3987]</dt><dd rel="dcterms:requires">M. Dürst; M. Suignard. <a href="http://www.ietf.org/rfc/rfc3987.txt"><cite>Internationalized Resource Identifiers (IRIs).</cite></a> January 2005. Internet RFC 3987. URL: <a href="http://www.ietf.org/rfc/rfc3987.txt">http://www.ietf.org/rfc/rfc3987.txt</a>
-</dd><dt id="bib-UNICODE">[UNICODE]</dt><dd rel="dcterms:requires">The Unicode Consortium. <a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html"><cite>The Unicode Standard.</cite></a>. Defined by: The Unicode Standard, Version 6.2.0, (Mountain View, CA: The Unicode Consortium, 2012. ISBN 978-1-936213-07-8) , as updated from time to time by the publication of new versions URL: <a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html">http://www.unicode.org/unicode/standard/versions/enumeratedversions.html</a>
-</dd><dt id="bib-XML-EXC-C14N">[XML-EXC-C14N]</dt><dd rel="dcterms:requires">Donald E. Eastlake 3rd; Joseph Reagle; John Boyer. <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/"><cite>Exclusive XML Canonicalization Version 1.0.</cite></a> 18 July 2002. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/">http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/</a>
-</dd><dt id="bib-XML-NAMES">[XML-NAMES]</dt><dd rel="dcterms:requires">Richard Tobin; et al. <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/"><cite>Namespaces in XML 1.0 (Third Edition).</cite></a> 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</a>
-</dd><dt id="bib-XML10">[XML10]</dt><dd rel="dcterms:requires">C. M. Sperberg-McQueen; et al. <a href="http://www.w3.org/TR/2008/REC-xml-20081126/"><cite>Extensible Markup Language (XML) 1.0 (Fifth Edition).</cite></a> 26 November 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</a>
-</dd><dt id="bib-XMLSCHEMA11-2">[XMLSCHEMA11-2]</dt><dd rel="dcterms:requires">Henry S. Thompson; et al. <a href="http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/"><cite>W3C XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes.</cite></a> 5 April 2012. W3C Recommendation URL: <a href="http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/">http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/</a>
-</dd></dl></div><div id="informative-references" typeof="bibo:Chapter" resource="#informative-references" rel="bibo:chapter" class="section"><h3><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography" about=""><dt id="bib-COOLURIS">[COOLURIS]</dt><dd rel="dcterms:references">Richard Cyganiak; Leo Sauermann. <a href="http://www.w3.org/TR/2008/NOTE-cooluris-20081203"><cite>Cool URIs for the Semantic Web.</cite></a> 3 December 2008. W3C Note. URL: <a href="http://www.w3.org/TR/2008/NOTE-cooluris-20081203">http://www.w3.org/TR/2008/NOTE-cooluris-20081203</a>
-</dd><dt id="bib-HTML-RDFA">[HTML-RDFA]</dt><dd rel="dcterms:references">Manu Sporny; et al. <a href="http://www.w3.org/TR/2011/WD-rdfa-in-html-20110525/"><cite>HTML+RDFa 1.1</cite></a> 25 May 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2011/WD-rdfa-in-html-20110525/">http://www.w3.org/TR/2011/WD-rdfa-in-html-20110525/</a>
-</dd><dt id="bib-N-TRIPLES">[N-TRIPLES]</dt><dd rel="dcterms:references">Jan Grant; Dave Beckett. <a href="http://www.w3.org/TR/rdf-testcases/#ntriples"><cite>N-Triples</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-testcases/#ntriples">http://www.w3.org/TR/rdf-testcases/#ntriples</a>
-</dd><dt id="bib-OWL2-OVERVIEW">[OWL2-OVERVIEW]</dt><dd rel="dcterms:references">W3C OWL Working Group. <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/"><cite>OWL 2 Web Ontology Language: Overview.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/">http://www.w3.org/TR/2009/REC-owl2-overview-20091027/</a>
-</dd><dt id="bib-RDF-MT">[RDF-MT]</dt><dd rel="dcterms:references">Patrick Hayes. <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210"><cite>RDF Semantics.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210">http://www.w3.org/TR/2004/REC-rdf-mt-20040210</a>
-</dd><dt id="bib-RDF-PRIMER">[RDF-PRIMER]</dt><dd rel="dcterms:references">Frank Manola; Eric Miller. <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/"><cite>RDF Primer.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">http://www.w3.org/TR/2004/REC-rdf-primer-20040210/</a>
-</dd><dt id="bib-RDF-SCHEMA">[RDF-SCHEMA]</dt><dd rel="dcterms:references">Dan Brickley; Ramanathan V. Guha. <a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210"><cite>RDF Vocabulary Description Language 1.0: RDF Schema.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">http://www.w3.org/TR/2004/REC-rdf-schema-20040210</a>
-</dd><dt id="bib-RDF-SPARQL-QUERY">[RDF-SPARQL-QUERY]</dt><dd rel="dcterms:references">Andy Seaborne; Eric Prud'hommeaux. <a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115"><cite>SPARQL Query Language for RDF.</cite></a> 15 January 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115">http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115</a>
-</dd><dt id="bib-RDF-SYNTAX-GRAMMAR">[RDF-SYNTAX-GRAMMAR]</dt><dd rel="dcterms:references">Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210"><cite>RDF/XML Syntax Specification (Revised).</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210">http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210</a>
-</dd><dt id="bib-RDF-TESTCASES">[RDF-TESTCASES]</dt><dd rel="dcterms:references">Jan Grant; Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210"><cite>RDF Test Cases.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210">http://www.w3.org/TR/2004/REC-rdf-testcases-20040210</a>
-</dd><dt id="bib-RDFA-PRIMER">[RDFA-PRIMER]</dt><dd rel="dcterms:references">Ben Adida, Ivan Herman, Manu Sporny. <a href="http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607"><cite>RDFa Primer.</cite></a> 07 June 2012. W3C Note. URL: <a href="http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607">http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607</a>
-</dd><dt id="bib-RFC3986">[RFC3986]</dt><dd rel="dcterms:references">T. Berners-Lee; R. Fielding; L. Masinter. <a href="http://www.ietf.org/rfc/rfc3986.txt"><cite>Uniform Resource Identifier (URI): Generic Syntax.</cite></a> January 2005. Internet RFC 3986. URL: <a href="http://www.ietf.org/rfc/rfc3986.txt">http://www.ietf.org/rfc/rfc3986.txt</a>
-</dd><dt id="bib-SWBP-N-ARYRELATIONS">[SWBP-N-ARYRELATIONS]</dt><dd rel="dcterms:references">Natasha Noy; Alan Rector. <a href="http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412"><cite>Defining N-ary Relations on the Semantic Web.</cite></a> 12 April 2006. W3C Note. URL: <a href="http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412">http://www.w3.org/TR/2006/NOTE-swbp-n-aryRelations-20060412</a>
-</dd><dt id="bib-SWBP-XSCH-DATATYPES">[SWBP-XSCH-DATATYPES]</dt><dd rel="dcterms:references">Jeremy J. Carroll; Jeff Z. Pan. <a href="http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314"><cite>XML Schema Datatypes in RDF and OWL.</cite></a> 14 March 2006. W3C Note. URL: <a href="http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314">http://www.w3.org/TR/2006/NOTE-swbp-xsch-datatypes-20060314</a>
-</dd><dt id="bib-TURTLE-TR">[TURTLE-TR]</dt><dd rel="dcterms:references">Eric Prud'hommeaux, Gavin Carothers. <a href="http://www.w3.org/TR/2012/WD-turtle-20120710/"><cite>Turtle: Terse RDF Triple Language.</cite></a> 10 July 2012. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2012/WD-turtle-20120710/">http://www.w3.org/TR/2012/WD-turtle-20120710/</a>
-</dd><dt id="bib-VOCAB-ORG">[VOCAB-ORG]</dt><dd rel="dcterms:references">Dave Reynolds. <a href="http://www.w3.org/TR/2012/WD-vocab-org-20121023/"><cite>An organization ontology.</cite></a> 23 October 2012. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2012/WD-vocab-org-20121023/">http://www.w3.org/TR/2012/WD-vocab-org-20121023/</a>
-</dd><dt id="bib-WEBARCH">[WEBARCH]</dt><dd rel="dcterms:references">Norman Walsh; Ian Jacobs. <a href="http://www.w3.org/TR/2004/REC-webarch-20041215/"><cite>Architecture of the World Wide Web, Volume One.</cite></a> 15 December 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-webarch-20041215/">http://www.w3.org/TR/2004/REC-webarch-20041215/</a>
-</dd><dt id="bib-WELL-KNOWN">[WELL-KNOWN]</dt><dd rel="dcterms:references">M. Nottingham; E. Hammer-Lahav. <a href="http://tools.ietf.org/html/rfc5785"><cite>Defining Well-Known Uniform Resource Identifiers (URIs).</cite></a> April 2010. Internet RFC 5785. URL: <a href="http://tools.ietf.org/html/rfc5785">http://tools.ietf.org/html/rfc5785</a>
-</dd><dt id="bib-XML-ID">[XML-ID]</dt><dd rel="dcterms:references">Daniel Veillard; Jonathan Marsh; Norman Walsh. <a href="http://www.w3.org/TR/2005/REC-xml-id-20050909"><cite>xml:id Version 1.0.</cite></a> 9 September 2005. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2005/REC-xml-id-20050909">http://www.w3.org/TR/2005/REC-xml-id-20050909</a>
-</dd><dt id="bib-XMLSCHEMA11-1">[XMLSCHEMA11-1]</dt><dd rel="dcterms:references">C. M. Sperberg-McQueen; Henry S. Thompson; Shudi Gao. <a href="http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/"><cite>W3C XML Schema Definition Language (XSD) 1.1 Part 1: Structures.</cite></a> 5 April 2012. W3C Recommendation URL: <a href="http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/">http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/</a>
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