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+ <title>RDF 1.1 Concepts and Abstract Syntax</title>
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+
+ <body class="h-entry"><div class="head">
+ <p>
+
+ <a href="http://www.w3.org/"><img width="72" height="48" src="https://www.w3.org/Icons/w3c_home" alt="W3C"></a>
+
+ </p>
+ <h1 class="title p-name" id="title">RDF 1.1 Concepts and Abstract Syntax</h1>
+
+ <h2 id="w3c-last-call-working-draft-04-july-2013"><abbr title="World Wide Web Consortium">W3C</abbr> Last Call Working Draft <time class="dt-published" datetime="2013-07-04">04 July 2013</time></h2>
+ <dl>
+
+ <dt>This version:</dt>
+ <dd><a class="u-url" href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130704/">http://www.w3.org/TR/2013/WD-rdf11-concepts-20130704/</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="https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html">https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html</a></dd>
+
+
+
+
+
+ <dt>Previous 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 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" class="p-org org h-org h-card" href="http://www.deri.ie/">DERI, NUI Galway</a></span>
+</dd>
+<dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="David Wood" href="http://about.me/david_wood">David Wood</a>, <a rel="foaf:workplaceHomepage" class="p-org org h-org h-card" href="http://3roundstones.com/">3 Round Stones</a></span>
+</dd>
+
+
+
+ </dl>
+
+
+
+
+
+ <p class="copyright">
+ <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> ©
+ 2004-2013
+
+ <a href="http://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup>
+ (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>,
+ <a href="http://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>,
+ <a href="http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved.
+ <abbr title="World Wide Web Consortium">W3C</abbr> <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 class="head">
+
+<section id="abstract" class="introductory" 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>
+</section><section id="sotd" class="introductory" 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 <abbr title="World Wide Web Consortium">W3C</abbr> publications and the latest revision
+ of this technical report can be found in the <a href="http://www.w3.org/TR/"><abbr title="World Wide Web Consortium">W3C</abbr> technical reports
+ index</a> at http://www.w3.org/TR/.</em>
+ </p>
+
+ <p>
+ This document was published by the <a href="http://www.w3.org/2011/rdf-wg/">RDF Working Group</a> as a Last Call Working Draft.
+
+ This document is intended to become a <abbr title="World Wide Web Consortium">W3C</abbr> 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>).
+
+ The Last Call period ends 06 September 2013.
+
+
+ All comments are welcome.</p>
+
+
+ <p>
+ Publication as a Last Call Working Draft does not imply endorsement by the <abbr title="World Wide Web Consortium">W3C</abbr> 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 is a Last Call Working Draft and thus the Working Group has determined that this document has satisfied the
+ relevant technical requirements and is sufficiently stable to advance through the Technical Recommendation process.
+ </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 <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
+
+
+
+
+ <abbr title="World Wide Web Consortium">W3C</abbr> 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 <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
+
+
+ </p>
+
+
+
+
+</section><section id="toc"><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 <abbr title="Internationalized Resource Identifier">IRI</abbr></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 Comparison</a></li></ul></li><li class="tocline"><a href="#section-dataset" class="tocxref"><span class="secno">4. </span>RDF Datasets</a><ul class="toc"><li class="tocline"><a href="#section-dataset-isomorphism" class="tocxref"><span class="secno">4.1 </span>RDF Dataset Comparison</a></li><li class="tocline"><a href="#section-dataset-conneg" class="tocxref"><span class="secno">4.2 </span>Content Negotiation of RDF Datasets</a></li></ul></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 IRIs</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-generalized-rdf" class="tocxref"><span class="secno">7. </span>Generalized RDF Triples, Graphs, and Datasets</a></li><li class="tocline"><a href="#section-Acknowledgments" class="tocxref"><span class="secno">8. </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-wd4" class="tocxref"><span class="secno">B.1 </span>Changes from 15 January 2013 WD to this version</a></li><li class="tocline"><a href="#changes-wd3" class="tocxref"><span class="secno">B.2 </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.3 </span>Changes from FPWD to 05 June 2012 WD</a></li><li class="tocline"><a href="#changes-fpwd" class="tocxref"><span class="secno">B.4 </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></section>
+
+</div>
+
+<section id="section-Introduction" class="informative" typeof="bibo:Chapter" resource="#section-Introduction" rel="bibo:chapter">
+ <!--OddPage--><h2><span class="secno">1. </span>Introduction</h2><p><em>This section is non-normative.</em></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" href="#bib-turtle">turtle</a></cite>]
+ and <a href="http://www.w3.org/TR/REC-rdf-syntax/">RDF/XML</a>
+ [<cite><a class="bibref" 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" 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" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>],</li>
+
+ <li>the <a href="http://www.w3.org/TR/rdf11-mt/">formal
+ model-theoretic semantics for RDF and RDFS</a> [<cite><a class="bibref" href="#bib-RDF-MT">RDF-MT</a></cite>].</li>
+ </ul>
+
+<section id="data-model" typeof="bibo:Chapter" resource="#data-model" rel="bibo:chapter">
+ <h3><span class="secno">1.1 </span>Graph-based Data Model</h3><p><em>This section is non-normative.</em></p>
+
+ <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>
+
+ <figure class="figure" id="fig-an-rdf-graph-with-two-nodes-subject-and-object-and-a-triple-connecting-them-predicate">
+ <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>
+ <figcaption>Fig. <span class="figno">1</span> <span class="fig-title">An RDF graph with two nodes (Subject and Object) and a triple connecting them (Predicate)</span></figcaption></figure>
+
+ <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-1" class="internalDFN">literals</a>,
+ and <a title="blank node" href="#dfn-blank-node" class="internalDFN">blank nodes</a>.</p>
+</section>
+
+
+<section id="resources-and-statements" typeof="bibo:Chapter" resource="#resources-and-statements" rel="bibo:chapter">
+ <h3><span class="secno">1.2 </span>Resources and Statements</h3>
+
+ <p>Any <a><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or <a href="#dfn-literal-1" class="internalDFN">literal</a> <dfn title="denote" id="dfn-denote">denotes</dfn>
+ something in the world (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 <abbr title="Internationalized Resource Identifier">IRI</abbr> 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>Asserting 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><abbr title="Internationalized Resource Identifier">IRI</abbr></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" 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-1" 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>
+</section>
+
+
+<section id="referents" typeof="bibo:Chapter" resource="#referents" rel="bibo:chapter">
+ <h3><span class="secno">1.3 </span>The Referent of an <abbr title="Internationalized Resource Identifier">IRI</abbr></h3>
+
+ <p>The <a href="#dfn-resource" class="internalDFN">resource</a> <a title="denote" href="#dfn-denote" class="internalDFN">denoted</a> by an <a><abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+ is also called its <dfn id="dfn-referent">referent</dfn>. For some IRIs with particular
+ meanings, such as those identifying XSD datatypes, the referent is
+ fixed by this specification. For all other IRIs, what exactly is
+ denoted by any given <abbr title="Internationalized Resource Identifier">IRI</abbr> is not defined by this specification. Other
+ specifications may fix <abbr title="Internationalized Resource Identifier">IRI</abbr> referents, or apply other constraints on
+ what may be the referent of any <abbr title="Internationalized Resource Identifier">IRI</abbr>.</p>
+
+ <p>Guidelines for determining the <a href="#dfn-referent" class="internalDFN">referent</a> of an <a><abbr title="Internationalized Resource Identifier">IRI</abbr></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" 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" href="#bib-COOLURIS">COOLURIS</a></cite>].
+ A very brief, informal and partial account follows:</p>
+
+ <ul>
+ <li>IRIs have global scope: Two different appearances of an <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ <a href="#dfn-denote" class="internalDFN">denote</a> the same <a href="#dfn-resource" class="internalDFN">resource</a>.</li>
+
+ <li>By social convention, the
+ <a href="http://www.w3.org/TR/webarch/#uri-ownership"><abbr title="Internationalized Resource Identifier">IRI</abbr> owner</a>
+ [<cite><a class="bibref" href="#bib-WEBARCH">WEBARCH</a></cite>] gets to say what what the intended (or usual)
+ referent of an <a><abbr title="Internationalized Resource Identifier">IRI</abbr></a> is. Applications and users need not
+ abide by this intended denotation, but there may be a loss of
+ interoperability with other applications and users if they do
+ not do so.</li>
+
+ <li>The <abbr title="Internationalized Resource Identifier">IRI</abbr> 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" href="#bib-vocab-org">vocab-org</a></cite>] specifies the intended 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> so that it
+ <a href="http://www.w3.org/TR/webarch/#uri-dereference">dereferences</a>
+ [<cite><a class="bibref" 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 characteristic 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 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.
+ However, those interactions are critical to the concept of
+ <em><a href="http://www.w3.org/DesignIssues/LinkedData.html">Linked Data</a></em> [<cite><a class="bibref" href="#bib-LINKED-DATA">LINKED-DATA</a></cite>],
+ which makes use of the RDF data model and serialization formats.</p>
+</section>
+
+<section id="vocabularies" typeof="bibo:Chapter" resource="#vocabularies" rel="bibo:chapter">
+ <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>
+ 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" 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" 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 begin with
+ a common substring known as a <dfn id="dfn-namespace-iri">namespace <abbr title="Internationalized Resource Identifier">IRI</abbr></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 class="simple">
+ <caption>Some example namespace prefixes and IRIs</caption>
+ <tbody><tr><th>Namespace prefix</th><th>Namespace <abbr title="Internationalized Resource Identifier">IRI</abbr></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" 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" 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 serialization formats 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 a
+ <a href="#dfn-namespace-prefix" class="internalDFN">namespace prefix</a> in order to assist readability. For example, the <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ <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 <abbr title="Internationalized Resource Identifier">IRI</abbr></a>” or “<a href="#dfn-rdf-vocabulary" class="internalDFN">RDF vocabulary</a>”.</p>
+</section>
+
+
+<section id="change-over-time" typeof="bibo:Chapter" resource="#change-over-time" rel="bibo:chapter">
+ <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><abbr title="Internationalized Resource Identifier">IRI</abbr></a>, once <a title="minting">minted</a>, should never
+ change its intended <a href="#dfn-referent" class="internalDFN">referent</a>. (See
+ <a href="http://www.w3.org/TR/webarch/#URI-persistence"><abbr title="Uniform Resource Identifier">URI</abbr>
+ persistence</a> [<cite><a class="bibref" href="#bib-WEBARCH">WEBARCH</a></cite>].)</li>
+ <li><a title="literal" href="#dfn-literal-1" 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>
+
+</section>
+
+
+<section id="managing-graphs" typeof="bibo:Chapter" resource="#managing-graphs" rel="bibo:chapter">
+ <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">combined</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><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or blank node. They are called
+ <a title="named graph" href="#dfn-named-graph" class="internalDFN">named graphs</a>, and the <abbr title="Internationalized Resource Identifier">IRI</abbr> or blank node
+ is called the <a href="#dfn-graph-name" class="internalDFN">graph name</a>.
+ The remaining graph does not have an associated <abbr title="Internationalized Resource Identifier">IRI</abbr>, 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>.</p>
+</section>
+
+
+<section id="entailment" typeof="bibo:Chapter" resource="#entailment" rel="bibo:chapter">
+ <h3><span class="secno">1.7 </span>Equivalence, Entailment and Inconsistency</h3>
+
+ <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. The union of two RDF graphs that do not share blank
+ nodes is their <a>conjunction</a>. If two <a href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>s share blank
+ nodes, then conjoining them may require merging as defined in the
+ RDF Semantics specification [<cite><a class="bibref" 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" 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" 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" 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>.
+ </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>
+</section>
+
+
+<section id="rdf-documents" typeof="bibo:Chapter" resource="#rdf-documents" rel="bibo:chapter">
+ <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" href="#bib-turtle">turtle</a></cite>], RDFa [<cite><a class="bibref" href="#bib-RDFA-PRIMER">RDFA-PRIMER</a></cite>], JSON-LD [<cite><a class="bibref" href="#bib-JSON-LD">JSON-LD</a></cite>],
+ RDF/XML [<cite><a class="bibref" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>], or N-Triples [<cite><a class="bibref" 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> may offer
+ many different ways to encode the same <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>
+</section>
+
+
+</section>
+
+
+<section id="conformance" typeof="bibo:Chapter" resource="#conformance" rel="bibo:chapter"><!--OddPage--><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" 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>
+</section>
+
+
+<section id="section-rdf-graph" typeof="bibo:Chapter" resource="#section-rdf-graph" rel="bibo:chapter">
+ <!--OddPage--><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>
+
+
+<section id="section-triples" typeof="bibo:Chapter" resource="#section-triples" rel="bibo:chapter">
+ <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><abbr title="Internationalized Resource Identifier">IRI</abbr></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><abbr title="Internationalized Resource Identifier">IRI</abbr></a></li>
+
+ <li>the <dfn id="dfn-object">object</dfn>, which is an <a><abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ a <a href="#dfn-literal-1" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> 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-1" 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>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class=""><a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>, <a title="literal" href="#dfn-literal-1" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr>,
+ 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>
+</section>
+
+
+<section id="section-IRIs" typeof="bibo:Chapter" resource="#section-IRIs" rel="bibo:chapter">
+ <h3><span class="secno">3.2 </span>IRIs</h3>
+
+ <p>An <dfn title="IRI" id="dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></dfn>
+ (Internationalized Resource Identifier) within an RDF graph
+ is a Unicode string [<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>] that conforms to the syntax
+ defined in RFC 3987 [<cite><a class="bibref" 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"><abbr title="Internationalized Resource Identifier">IRI</abbr> 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" 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"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><div class="" id="note-iris">
+ <p><strong>URIs and IRIs:</strong>
+ IRIs are a generalization of
+ <dfn title="URI" id="dfn-uri"><abbr title="Uniform Resource Identifier">URI</abbr>s</dfn> [<cite><a class="bibref" href="#bib-RFC3986">RFC3986</a></cite>] that permits a much wider range of Unicode characters.
+ Every absolute <abbr title="Uniform Resource Identifier">URI</abbr> and URL is an <abbr title="Internationalized Resource Identifier">IRI</abbr>, but not every <abbr title="Internationalized Resource Identifier">IRI</abbr> is an <abbr title="Uniform Resource Identifier">URI</abbr>.
+ 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" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr></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 <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ can be established</a> [<cite><a class="bibref" href="#bib-RFC3986">RFC3986</a></cite>].</p>
+
+ <p><strong><abbr title="Internationalized Resource Identifier">IRI</abbr> 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" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> 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 <abbr title="Internationalized Resource Identifier">IRI</abbr></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" href="#bib-NFC">NFC</a></cite>]</li>
+ </ul>
+ </div></div>
+</section>
+
+
+<section id="section-Graph-Literal" typeof="bibo:Chapter" resource="#section-Graph-Literal" rel="bibo:chapter">
+ <h3><span class="secno">3.3 </span>Literals</h3>
+
+ <p>Literals are used for values such as strings, numbers and dates.</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" href="#bib-UNICODE">UNICODE</a></cite>] string,
+ which <em class="rfc2119" title="SHOULD">SHOULD</em> be in Normal Form C [<cite><a class="bibref" href="#bib-NFC">NFC</a></cite>],</li>
+ <li>a <dfn id="dfn-datatype-iri">datatype <abbr title="Internationalized Resource Identifier">IRI</abbr></dfn>, being an <a><abbr title="Internationalized Resource Identifier">IRI</abbr></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 <abbr title="Internationalized Resource Identifier">IRI</abbr></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" 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" href="#bib-BCP47">BCP47</a></cite>]. Lexical representations of language tags <em class="rfc2119" title="MAY">MAY</em> be converted to
+ lower case. The value space of language tags is always in lower case.</li>
+ <li>A badly formed language tag <em class="rfc2119" title="MUST">MUST</em> be treated as a syntax error.</li>
+ </ul>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class="" id="note-language-tag-regex">
+ Implementors might wish to note that language tags conform to the
+ regular expression <code>’@’ [a-zA-Z]{1,8} (’-’
+ [a-zA-Z0-9]{1,8})*</code>
+ before normalizing to lowercase.</p></div>
+
+ <p>Multiple literals may have the same lexical form.</p>
+
+ <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 <abbr title="Internationalized Resource Identifier">IRI</abbr> 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-1" class="internalDFN">literals</a> with the <a href="#dfn-datatype-iri" class="internalDFN">datatype <abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+ <code>http://www.w3.org/2001/XMLSchema#string</code>.</p>
+
+ <p><dfn id="dfn-literal-term-equality">Literal term equality</dfn>: Two literals are term-equal
+ (the same RDF literal) 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>
+
+ <p>Two literals can have the same value without being the same
+ <a title="RDF Term" href="#dfn-rdf-term" class="internalDFN">RDF term</a>. For example:
+
+ </p><pre> "1"^^xs:integer
+ "01"^^xs:integer
+ </pre>
+
+ <p>denote the same value, but are not the same literal
+ <a title="RDF Term" href="#dfn-rdf-term" class="internalDFN">RDF terms</a> and are not term-equals.</p>
+
+ <p>The <dfn id="dfn-literal-value">literal value</dfn> associated with a <a href="#dfn-literal-1" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr></a> is not
+ <a title="recognized datatype IRIs" href="#dfn-recognized-datatype-iris" class="internalDFN">recognized</a> by an
+ implementation,</strong> then the literal value
+ is not defined by this specification.</li>
+ <li>Let <var>d</var> be the <a href="#dfn-referent" class="internalDFN">referent</a> of the
+ datatype <abbr title="Internationalized Resource Identifier">IRI</abbr> in the set of <a href="#dfn-recognized-datatype-iris" class="internalDFN">recognized datatype IRIs</a>.
+ <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 <var>d</var>,</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 <var>d</var> to the <a href="#dfn-lexical-form" class="internalDFN">lexical form</a>.</li>
+ <li><strong>Otherwise</strong>, the <dfn id="dfn-literal-1">literal</dfn> is ill-typed,
+ and no literal value can be associated with the literal. Such a case
+ produces a semantic inconsistency but is not <em>syntactically</em>
+ ill-formed and implementations <em class="rfc2119" title="MUST">MUST</em> accept ill-typed literals and produce
+ RDF graphs from them. Implementations <em class="rfc2119" title="MAY">MAY</em> produce warnings when
+ encountering ill-typed literals.</li>
+ </ol>
+
+</section>
+
+
+<section id="section-blank-nodes" typeof="bibo:Chapter" resource="#section-blank-nodes" rel="bibo:chapter">
+ <h3><span class="secno">3.4 </span>Blank Nodes</h3>
+
+ <p><dfn title="blank node" id="dfn-blank-node">Blank nodes</dfn> are disjoint from
+ <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a> and <a title="literal" href="#dfn-literal-1" class="internalDFN">literals</a>. Otherwise,
+ the set of possible blank nodes is arbitrary. RDF makes no reference to
+ any internal structure of blank nodes.</p>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class="" 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. Implementations that handle blank node
+ identifiers in concrete syntaxes need to be careful not to create the
+ same blank node from multiple occurences of the same blank node identifier
+ except in situations where this is supported by the syntax.</p></div>
+</section>
+
+
+<section id="section-skolemization" typeof="bibo:Chapter" resource="#section-skolemization" rel="bibo:chapter">
+ <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">mint</a> a new, globally
+ unique <abbr title="Internationalized Resource Identifier">IRI</abbr> (a <dfn id="dfn-skolem-iri">Skolem <abbr title="Internationalized Resource Identifier">IRI</abbr></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 blank
+ nodes. This allows a system to map IRIs back to blank nodes
+ 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> [<cite><a class="bibref" href="#bib-RFC5785">RFC5785</a></cite>] with the registered
+ name <code>genid</code>. This is an <abbr title="Internationalized Resource Identifier">IRI</abbr> 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 <abbr title="Internationalized Resource Identifier">IRI</abbr>:</p>
+
+ <pre>http://example.com/.well-known/genid/d26a2d0e98334696f4ad70a677abc1f6</pre>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class="">RFC 5785 [<cite><a class="bibref" href="#bib-RFC5785">RFC5785</a></cite>] only specifies well-known URIs,
+ not IRIs. For the purpose of this document, a well-known <abbr title="Internationalized Resource Identifier">IRI</abbr> is any
+ <abbr title="Internationalized Resource Identifier">IRI</abbr> that results in a well-known <abbr title="Uniform Resource Identifier">URI</abbr> after <abbr title="Internationalized Resource Identifier">IRI</abbr>-to-<abbr title="Uniform Resource Identifier">URI</abbr> mapping [<cite><a class="bibref" href="#bib-RFC3987">RFC3987</a></cite>].</p></div>
+</section>
+
+
+<section id="graph-isomorphism" typeof="bibo:Chapter" resource="#graph-isomorphism" rel="bibo:chapter">
+ <h3><span class="secno">3.6 </span>Graph Comparison</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> (that is, they have an identical
+ form) 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-1" 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"><abbr title="Internationalized Resource Identifier">IRI</abbr> equality</a>, <a href="#dfn-literal-term-equality" class="internalDFN">literal term 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" href="#bib-RDF-TESTCASES">RDF-TESTCASES</a></cite>] specification.</p>
+</section>
+
+</section>
+
+
+<section id="section-dataset" typeof="bibo:Chapter" resource="#section-dataset" rel="bibo:chapter">
+ <!--OddPage--><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><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or a blank node
+ (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 title="RDF Dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>.</p>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="3"><span>Note</span></div><div class="" 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 title="RDF Dataset" 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>
+
+ <p>Blank nodes as graph names are new. Existing SPARQL implementations
+ might not accept this new feature for some time, so the use of blank
+ nodes as graph names can cause interoperability problems.
+ <a href="#section-skolemization">Skolemizing</a> blank nodes used as
+ graph names can be used to overcome these interoperability problems.</p>
+
+ </div></div>
+
+<section id="section-dataset-isomorphism" typeof="bibo:Chapter" resource="#section-dataset-isomorphism" rel="bibo:chapter">
+ <h3><span class="secno">4.1 </span>RDF Dataset Comparison</h3>
+
+ <p id="section-dataset-equality">Two <a title="RDF Dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a>
+ (the RDF dataset <var>D1</var> with default graph <var>DG1</var> and named
+ graph <var>NG1</var> and the RDF dataset <var>D2</var> with default graph
+ <var>DG2</var> and named graph <var>NG2</var>) are
+ <dfn title="dataset isomorphism" id="dfn-dataset-isomorphism">dataset-isomorphic</dfn> if and only if:</p>
+ <ol>
+ <li><var>DG1</var> and <var>DG2</var> are graph-isomorphic;</li>
+ <li>For each <var>(n1,g1)</var> in <var>NG1</var>, there exists
+ <var>(n2,g2)</var> in <var>NG2</var> such that <var>n1</var>=<var>n2</var>
+ and <var>g1</var> and <var>g2</var> are graph-isomorphic;</li>
+ <li>For each <var>(n2,g2)</var> in <var>NG2</var>, there exists
+ <var>(n1,g1)</var> in <var>NG1</var> such that <var>n1</var>=<var>n2</var>
+ and <var>g1</var> and <var>g2</var> are graph-isomorphic.</li>
+ </ol>
+
+</section>
+
+<section id="section-dataset-conneg" class="informative" typeof="bibo:Chapter" resource="#section-dataset-conneg" rel="bibo:chapter">
+ <h3><span class="secno">4.2 </span>Content Negotiation of RDF Datasets</h3><p><em>This section is non-normative.</em></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" href="#bib-WEBARCH">WEBARCH</a></cite>]. A representation may be returned in an RDF serialization
+ format that supports the expression of both <a title="RDF Dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF datasets</a> and
+ <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graphs</a>. If an <a title="RDF Dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF dataset</a>
+ is returned and the consumer is expecting an <a title="RDF graph" href="#dfn-rdf-graph" class="internalDFN">RDF graph</a>,
+ the consumer is expected to use the <a title="RDF Dataset" href="#dfn-rdf-dataset" class="internalDFN">RDF dataset's</a> default graph.</p>
+
+</section>
+
+</section>
+
+
+<section id="section-Datatypes" typeof="bibo:Chapter" resource="#section-Datatypes" rel="bibo:chapter">
+ <!--OddPage--><h2><span class="secno">5. </span>Datatypes</h2>
+
+ <p>Datatypes are used with RDF <a title="literal" href="#dfn-literal-1" 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" 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-recognized-datatype-iris" class="internalDFN">recognized datatype IRIs</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" 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>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="3"><span>Note</span></div><p class=""><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 <abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#langString</code>.
+ No datatype is formally defined for this <abbr title="Internationalized Resource Identifier">IRI</abbr> 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> is the set
+ of all pairs of strings and language tags.</p></div>
+
+ <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-1" class="internalDFN">literals</a> that can be defined using this
+ datatype are:</p>
+
+ <table class="simple">
+ <caption>This table lists the literals of type xsd:boolean.</caption>
+ <tbody><tr>
+ <th>Literal</th>
+ <th>Value</th>
+ </tr>
+ <tr>
+ <td><“<code>true</code>”, <code>xsd:boolean</code>></td>
+ <td><em><strong>true</strong></em></td>
+ </tr>
+ <tr>
+ <td><“<code>false</code>”, <code>xsd:boolean</code>></td>
+ <td><em><strong>false</strong></em></td>
+ </tr>
+ <tr>
+ <td><“<code>1</code>”, <code>xsd:boolean</code>></td>
+ <td><em><strong>true</strong></em></td>
+ </tr>
+ <tr>
+ <td><“<code>0</code>”, <code>xsd:boolean</code>></td>
+ <td><em><strong>false</strong></em></td>
+ </tr>
+ </tbody></table>
+
+
+<section id="xsd-datatypes" typeof="bibo:Chapter" resource="#xsd-datatypes" rel="bibo:chapter">
+ <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" 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>
+
+ <p>Readers might note that the xsd:hexBinary and xsd:base64Binary
+ datatypes are the only safe datatypes for transferring binary
+ information.</p>
+
+ <table class="simple">
+ <caption>A list of the RDF-compatible XSD types, with short descriptions"</caption>
+ <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 (but not all Unicode 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" 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"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><div class="">
+ <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>
+
+</section>
+
+
+<section id="section-html" typeof="bibo:Chapter" resource="#section-html" rel="bibo:chapter">
+ <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-1" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> 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" 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" 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" 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" href="#bib-DOM4">DOM4</a></cite>]
+ that result from applying the
+ <a href="http://www.w3.org/TR/html5/syntax.html#parsing-html-fragments">HTML fragment parsing algorithm</a> [<cite><a class="bibref" 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" 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>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class="" 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>
+</section>
+
+<section id="section-XMLLiteral" typeof="bibo:Chapter" resource="#section-XMLLiteral" rel="bibo:chapter">
+ <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-1" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> denoting this <a href="#dfn-datatype" class="internalDFN">datatype</a></dt>
+
+ <dd>is
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>.</dd>
+
+ <dt id="XMLLiteral-lexical-space">The <a href="#dfn-lexical-space" class="internalDFN">lexical space</a></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" 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" href="#bib-XML-NAMES">XML-NAMES</a></cite>].</dd>
+
+ <dt id="XMLLiteral-value-space">The <a href="#dfn-value-space" class="internalDFN">value space</a></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" 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 <a href="#dfn-lexical-to-value-mapping" class="internalDFN">lexical-to-value mapping</a></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" 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 <a>canonical mapping</a></dt>
+ <dd>defines a
+ <a href="http://www.w3.org/TR/xmlschema11-2/#dt-canonical-mapping">canonical lexical form</a>
+ [<cite><a class="bibref" 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" href="#bib-XML-EXC-C14N">XML-EXC-C14N</a></cite>].
+
+ </dd></dl>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class="">Any XML namespace declarations (<code>xmlns</code>),
+ language annotation (<code>xml:lang</code>) or base <abbr title="Uniform Resource Identifier">URI</abbr>
+ 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" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>]).</p></div>
+</section>
+
+<section id="datatype-maps" typeof="bibo:Chapter" resource="#datatype-maps" rel="bibo:chapter">
+ <h3><span class="secno">5.4 </span>Datatype IRIs</h3>
+
+ <p>Datatypes are identified by <a title="IRI" href="#dfn-iri" class="internalDFN">IRIs</a>. If
+ <var>D</var> is a set of IRIs which are used to refer to
+ datatypes, then the elements of <var>D</var> are called <dfn id="dfn-recognized-datatype-iris">recognized
+ datatype IRIs</dfn>. Recognized IRIs have fixed
+ <a href="#referents">referents</a>, which <em class="rfc2119" title="MUST">MUST</em> satisfy these
+ conditions:
+
+ </p><ol>
+ <li>If the <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</code>
+ is recognized then it refers to the datatype
+ <code>rdf:XMLLiteral</code>;</li>
+ <li>If the <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#HTML</code>
+ is recognized then it refers to the datatype <code>rdf:HTML</code>;</li>
+ <li>If any <abbr title="Internationalized Resource Identifier">IRI</abbr> of the form
+ <code>http://www.w3.org/2001/XMLSchema#xxx</code>
+ is recognized then it refers to the RDF-compatible XSD type
+ named <code>xsd:xxx</code>, for every XSD type listed in
+ <a href="#xsd-datatypes">section 5.1</a>.</li>
+ </ol>
+
+ <p>Semantic extensions of RDF <em class="rfc2119" title="MAY">MAY</em> recognize other datatype IRIs
+ and require them to refer to a fixed datatype.</p>
+
+ <p>RDF processors are not required to recognize datatype IRIs.
+ Any literal typed with an unrecognized <abbr title="Internationalized Resource Identifier">IRI</abbr> is treated just like
+ an unknown <abbr title="Internationalized Resource Identifier">IRI</abbr>, i.e. as referring to an unknown thing. Applications
+ <em class="rfc2119" title="MAY">MAY</em> give a warning message if they are unable to determine the
+ referent of an <abbr title="Internationalized Resource Identifier">IRI</abbr> used in a typed literal, but they <em class="rfc2119" title="SHOULD NOT">SHOULD NOT</em>
+ reject such RDF as either a syntactic or semantic error.</p><p>
+
+ </p><p>Other specifications
+ <em class="rfc2119" title="MAY">MAY</em> impose additional constraints on <a>datatype IRIs</a>,
+ for example, require support for certain datatypes.</p>
+
+ <div class="note"><div class="note-title" role="heading" aria-level="4"><span>Note</span></div><p class="" id="note-custom-datatypes">The Web Ontology Language
+ [<cite><a class="bibref" 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" href="#bib-SWBP-XSCH-DATATYPES">SWBP-XSCH-DATATYPES</a></cite>]. RDF implementations
+ are not required to support either of these facilities.</p></div>
+</section>
+
+</section>
+
+
+<section id="section-fragID" class="informative" typeof="bibo:Chapter" resource="#section-fragID" rel="bibo:chapter">
+ <!--OddPage--><h2><span class="secno">6. </span>Fragment Identifiers</h2><p><em>This section is non-normative.</em></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" 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><abbr title="Internationalized Resource Identifier">IRI</abbr></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" 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><abbr title="Internationalized Resource Identifier">IRI</abbr></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" href="#bib-XML-ID">XML-ID</a></cite>] is used
+ in an RDF/XML document, then the corresponding <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ 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" 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><abbr title="Internationalized Resource Identifier">IRI</abbr></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>
+</section>
+
+<section id="section-generalized-rdf" class="informative" typeof="bibo:Chapter" resource="#section-generalized-rdf" rel="bibo:chapter">
+ <!--OddPage--><h2><span class="secno">7. </span>Generalized RDF Triples, Graphs, and Datasets</h2><p><em>This section is non-normative.</em></p>
+
+<p>It is sometimes convenient to loosen the requirements on <a href="#dfn-rdf-triple" class="internalDFN">RDF
+ triple</a>s. For example, the completeness of the RDFS entailment rules
+ is easier to show with a generalization of RDF triples. Note that any
+ users of these generalized notions need to be aware that their use may
+ cause interoperability problems, and that there is no requirement on the
+ part of any RDF tool to accept, process, or produce anything beyond
+ regular RDF triples, graphs, and datasets. </p>
+
+ <p>A <dfn id="dfn-generalized-rdf-triple">generalized RDF triple</dfn> is an RDF triple generalized so
+ that subjects, predicates, and objects all allowed to be IRIs, blank
+ nodes, or literals. A <dfn id="dfn-generalized-rdf-graph">generalized RDF graph</dfn> is an RDF graph of
+ generalized RDF triples, i.e., a set of generalized RDF triples.
+ A <dfn id="dfn-generalized-rdf-dataset">generalized RDF dataset</dfn> is an RDF dataset of generalized RDF
+ graphs where graph labels can be IRIs, blank nodes, or literals.</p>
+
+</section>
+
+<section id="section-Acknowledgments" class="informative" typeof="bibo:Chapter" resource="#section-Acknowledgments" rel="bibo:chapter">
+ <!--OddPage--><h2><span class="secno">8. </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, Tim Berners-Lee,
+ 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>
+</section>
+
+
+<section class="appendix informative" id="changes" typeof="bibo:Chapter" resource="#changes" rel="bibo:chapter">
+ <!--OddPage--><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 <abbr title="Uniform Resource Identifier">URI</abbr> Reference</dfn>” instead of “<abbr title="Internationalized Resource Identifier">IRI</abbr>” 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" href="#bib-RFC3986">RFC3986</a></cite>].</p>
+
+ <p>In earlier versions of RDF, <a title="literal" href="#dfn-literal-1" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr></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" 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 might 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 <abbr title="World Wide Web Consortium">W3C</abbr>-recommended concrete syntax.
+ Currently a literal with type xsd:string containing the #x0 character
+ is an ill-typed literal.</p>
+
+</section>
+
+
+<section class="appendix informative" id="change-log" typeof="bibo:Chapter" resource="#change-log" rel="bibo:chapter">
+ <!--OddPage--><h2><span class="secno">B. </span>Change Log</h2><p><em>This section is non-normative.</em></p>
+
+<section class="appendix" id="changes-wd4" typeof="bibo:Chapter" resource="#changes-wd4" rel="bibo:chapter">
+ <h3><span class="secno">B.1 </span>Changes from 15 January 2013 WD to this version</h3><p><em>This section is non-normative.</em></p>
+
+ <p>This section lists changes from the
+ <a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/">15 January 2013 Working Draft (WD)</a> to this Editor's Draft of
+ <em>RDF 1.1 Concepts and Abstract Syntax</em>.</p>
+
+ <ul>
+ <li>2013-07-03: Editorial changes in response to <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jul/0003.html">a review by Markus Lanthaler</a> and a <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jul/0026.html">related request</a></li>
+ <li>2013-06-27: Added informative section on generalized RDF triples, graphs, and
+ datasets.</li>
+ <li>2013-06-27: Added caution on the use of graph names as blank nodes.</li>
+ <li>2013-06-19: Noted that RDF Dataset graph names may be blank nodes (<a href="https://www.w3.org/2011/rdf-wg/track/actions/274">ACTION-274</a>, <a href="https://www.w3.org/2013/meeting/rdf-wg/2013-06-12#resolution_1">resolution</a>)</li>
+ <li>2013-06-19: Changes in response to <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2013May/0221.html">a
+ review by Peter Patel-Schneider</a></li>
+ <li>2013-06-05: Minor change to note to specify the value space and lexical space of language tags (<a href="http://www.w3.org/2011/rdf-wg/track/actions/265">ACTION-265</a>, <a href="https://www.w3.org/2013/meeting/rdf-wg/2013-05-22#resolution_3">resolution</a>)</li>
+ <li>2013-05-08: Minor change to note that a badly formed language tag is a syntax error (<a href="http://www.w3.org/2011/rdf-wg/track/actions/262">ACTION-262</a>)</li>
+ <li>2013-05-08: Migrated language related to datatype maps to recognized datatype IRIs (<a href="http://www.w3.org/2011/rdf-wg/track/issues/118">ISSUE-118</a>)</li>
+ <li>2013-05-08: Editorial changes in response to <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2013May/0058.html">a discussion of literal equality</a></li>
+ <li>2013-05-08: Editorial changes in response to <a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2013May/0075.html">a review by Sandro Hawke</a></li>
+ <li>2013-05-07: Revised the definition of blank nodes (<a href="http://www.w3.org/2011/rdf-wg/track/issues/107">ISSUE-107</a>)</li>
+ <li>2013-05-07: Defined the consequence of a literal being ill-typed (<a href="http://www.w3.org/2011/rdf-wg/track/issues/109">ISSUE-109</a>)</li>
+ <li>2013-05-07: Clarified the existence of null control characters in xsd:strings (<a href="http://www.w3.org/2011/rdf-wg/track/issues/126">ISSUE-126</a>)</li>
+ <li>2013-05-07: Added a definition of RDF Dataset isomorphism (<a href="http://www.w3.org/2011/rdf-wg/track/issues/111">ISSUE-111</a>)</li>
+ <li>2013-05-07: Addressed content negotiation as it relates to graphs and datasets (<a href="http://www.w3.org/2011/rdf-wg/track/issues/105">ISSUE-105</a>)</li>
+ </ul>
+</section>
+
+<section class="appendix" id="changes-wd3" typeof="bibo:Chapter" resource="#changes-wd3" rel="bibo:chapter">
+ <h3><span class="secno">B.2 </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 Editor's 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-1" 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 note on empty named graphs (<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">datatype maps</a></li>
+ </ul>
+</section>
+
+
+<section class="appendix" id="changes-wd2" typeof="bibo:Chapter" resource="#changes-wd2" rel="bibo:chapter">
+ <h3><span class="secno">B.3 </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 <abbr title="Internationalized Resource Identifier">IRI</abbr> 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" href="#bib-XMLSCHEMA11-1">XMLSCHEMA11-1</a></cite>] and [<cite><a class="bibref" 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>datatype map</a>, both adapted from previous content in [<cite><a class="bibref" 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 <abbr title="Internationalized Resource Identifier">IRI</abbr> <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>
+</section>
+
+<section class="appendix" id="changes-fpwd" typeof="bibo:Chapter" resource="#changes-fpwd" rel="bibo:chapter">
+ <h3><span class="secno">B.4 </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 <abbr title="Uniform Resource Identifier">URI</abbr> References section with <a href="#section-IRIs">new section on IRIs</a>, and changed “RDF <abbr title="Uniform Resource Identifier">URI</abbr> Reference” to “<abbr title="Internationalized Resource Identifier">IRI</abbr>” 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 <abbr title="World Wide Web Consortium">W3C</abbr> 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>
+</section>
+
+</section>
+
+
+
+
+<div id="cliptodevonthink-is-installed"></div><section id="references" class="appendix" typeof="bibo:Chapter" resource="#references" rel="bibo:chapter"><!--OddPage--><h2><span class="secno">C. </span>References</h2><section id="normative-references" typeof="bibo:Chapter" resource="#normative-references" rel="bibo:chapter"><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; Lachlan Hunt; Ms2ger. <a href="http://www.w3.org/TR/dom/"><cite>DOM4</cite></a>. 6 December 2012. W3C Working Draft. URL: <a href="http://www.w3.org/TR/dom/">http://www.w3.org/TR/dom/</a>
+</dd><dt id="bib-HTML5">[HTML5]</dt><dd rel="dcterms:requires">Robin Berjon et al. <a href="http://www.w3.org/TR/html5/"><cite>HTML5</cite></a>. 17 December 2012. W3C Candidate Recommendation. URL: <a href="http://www.w3.org/TR/html5/">http://www.w3.org/TR/html5/</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-RDF-MT">[RDF-MT]</dt><dd rel="dcterms:requires">Patrick Hayes. <a href="http://www.w3.org/TR/rdf-mt/"><cite>RDF Semantics</cite></a>. 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-mt/">http://www.w3.org/TR/rdf-mt/</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. RFC. 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"><a href="http://www.unicode.org/versions/latest/"><cite>The Unicode Standard</cite></a>. URL: <a href="http://www.unicode.org/versions/latest/">http://www.unicode.org/versions/latest/</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/xml-exc-c14n/"><cite>Exclusive XML Canonicalization Version 1.0</cite></a>. 18 July 2002. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xml-exc-c14n/">http://www.w3.org/TR/xml-exc-c14n/</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/xml-names/"><cite>Namespaces in XML 1.0 (Third Edition)</cite></a>. 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xml-names/">http://www.w3.org/TR/xml-names/</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/xml/"><cite>Extensible Markup Language (XML) 1.0 (Fifth Edition)</cite></a>. 26 November 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xml/">http://www.w3.org/TR/xml/</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/xmlschema11-2/"><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/xmlschema11-2/">http://www.w3.org/TR/xmlschema11-2/</a>
+</dd></dl></section><section id="informative-references" typeof="bibo:Chapter" resource="#informative-references" rel="bibo:chapter"><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/cooluris/"><cite>Cool URIs for the Semantic Web</cite></a>. 3 December 2008. W3C Note. URL: <a href="http://www.w3.org/TR/cooluris/">http://www.w3.org/TR/cooluris/</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/rdfa-in-html/"><cite>HTML+RDFa 1.1</cite></a>. 25 May 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/rdfa-in-html/">http://www.w3.org/TR/rdfa-in-html/</a>
+</dd><dt id="bib-JSON-LD">[JSON-LD]</dt><dd rel="dcterms:references">Manu Sporny; Gregg Kellogg; Markus Lanthaler. <a href="http://www.w3.org/TR/json-ld/"><cite>JSON-LD 1.0</cite></a>. 11 April 2013. W3C Working Draft. URL: <a href="http://www.w3.org/TR/json-ld/">http://www.w3.org/TR/json-ld/</a>
+</dd><dt id="bib-LINKED-DATA">[LINKED-DATA]</dt><dd rel="dcterms:references">Tim Berners-Lee. <a href="http://www.w3.org/DesignIssues/LinkedData.html"><cite>Linked Data Design Issues</cite></a>. 27 July 2006. W3C-Internal Document. URL: <a href="http://www.w3.org/DesignIssues/LinkedData.html">http://www.w3.org/DesignIssues/LinkedData.html</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/owl2-overview/"><cite>OWL 2 Web Ontology Language: Overview</cite></a>. 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/owl2-overview/">http://www.w3.org/TR/owl2-overview/</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/rdf-primer/"><cite>RDF Primer</cite></a>. 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-primer/">http://www.w3.org/TR/rdf-primer/</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/rdf-schema/"><cite>RDF Vocabulary Description Language 1.0: RDF Schema</cite></a>. 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-schema/">http://www.w3.org/TR/rdf-schema/</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/rdf-sparql-query/"><cite>SPARQL Query Language for RDF</cite></a>. 15 January 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-sparql-query/">http://www.w3.org/TR/rdf-sparql-query/</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/rdf-syntax-grammar/"><cite>RDF/XML Syntax Specification (Revised)</cite></a>. 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-syntax-grammar/">http://www.w3.org/TR/rdf-syntax-grammar/</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/rdf-testcases/"><cite>RDF Test Cases</cite></a>. 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/rdf-testcases/">http://www.w3.org/TR/rdf-testcases/</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/rdfa-primer/"><cite>RDFa Primer</cite></a>. 07 June 2012. W3C Note. URL: <a href="http://www.w3.org/TR/rdfa-primer/">http://www.w3.org/TR/rdfa-primer/</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 (RFC 3986)</cite></a>. January 2005. RFC. URL: <a href="http://www.ietf.org/rfc/rfc3986.txt">http://www.ietf.org/rfc/rfc3986.txt</a>
+</dd><dt id="bib-RFC5785">[RFC5785]</dt><dd rel="dcterms:references">Mark Nottingham; Eran Hammer-Lahav. <a href="http://www.rfc-editor.org/rfc/rfc5785.txt"><cite>Defining Well-Known Uniform Resource Identifiers (URIs) (RFC 5785)</cite></a>. April 2010. RFC. URL: <a href="http://www.rfc-editor.org/rfc/rfc5785.txt">http://www.rfc-editor.org/rfc/rfc5785.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/swbp-n-aryRelations/"><cite>Defining N-ary Relations on the Semantic Web</cite></a>. 12 April 2006. W3C Note. URL: <a href="http://www.w3.org/TR/swbp-n-aryRelations/">http://www.w3.org/TR/swbp-n-aryRelations/</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/swbp-xsch-datatypes/"><cite>XML Schema Datatypes in RDF and OWL</cite></a>. 14 March 2006. W3C Note. URL: <a href="http://www.w3.org/TR/swbp-xsch-datatypes/">http://www.w3.org/TR/swbp-xsch-datatypes/</a>
+</dd><dt id="bib-WEBARCH">[WEBARCH]</dt><dd rel="dcterms:references">Norman Walsh; Ian Jacobs. <a href="http://www.w3.org/TR/webarch/"><cite>Architecture of the World Wide Web, Volume One</cite></a>. 15 December 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/webarch/">http://www.w3.org/TR/webarch/</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/xml-id/"><cite>xml:id Version 1.0</cite></a>. 9 September 2005. W3C Recommendation. URL: <a href="http://www.w3.org/TR/xml-id/">http://www.w3.org/TR/xml-id/</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/xmlschema11-1/"><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/xmlschema11-1/">http://www.w3.org/TR/xmlschema11-1/</a>
+</dd><dt id="bib-n-triples">[n-triples]</dt><dd rel="dcterms:references">Gavin Carothers. <a href="http://www.w3.org/TR/n-triples/"><cite>N-Triples</cite></a>. 9 April 2013. W3C Note. URL: <a href="http://www.w3.org/TR/n-triples/">http://www.w3.org/TR/n-triples/</a>
+</dd><dt id="bib-turtle">[turtle]</dt><dd rel="dcterms:references">Eric Prud'hommeaux; Gavin Carothers. <a href="http://www.w3.org/TR/turtle/"><cite>Turtle</cite></a>. 19 February 2013. W3C Candidate Recommendation. URL: <a href="http://www.w3.org/TR/turtle/">http://www.w3.org/TR/turtle/</a>
+</dd><dt id="bib-vocab-org">[vocab-org]</dt><dd rel="dcterms:references">Dave Reynolds. <a href="http://www.w3.org/TR/vocab-org/"><cite>The Organization Ontology</cite></a>. 25 June 2013. W3C Candidate Recommendation. URL: <a href="http://www.w3.org/TR/vocab-org/">http://www.w3.org/TR/vocab-org/</a>
+</dd></dl></section></section></body></html>
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