--- a/rdf-concepts/index.html Sun Nov 18 20:38:25 2012 -0500
+++ b/rdf-concepts/index.html Wed Nov 21 19:20:59 2012 +0000
@@ -141,13 +141,8 @@
<h2>Introduction</h2>
<p class="issue">This is a work-in-progress Working Draft. Various open
- issues are flagged throughout the text with boxes like this. Feedback
- on these issues is particularly welcome.</p>
-
- <p class="issue">In some sections, the content is overwhelmed by
- informative Notes. Are they necessary? Can some be deleted or be moved
- to other documents? Can some be merged or streamlined? This is
- <a href="https://www.w3.org/2011/rdf-wg/track/issues/104">ISSUE-104</a>.</p>
+ issues are flagged throughout the text with boxes like this.
+ <a href="#sotd">Feedback</a> on these issues is particularly welcome.</p>
<p>The <em>Resource Description Framework</em> (RDF) is a framework
for representing information in the Web.</p>
@@ -331,19 +326,16 @@
sets, adding or removing <a title="RDF triple">triples</a> from an
RDF graph yields a different RDF graph.</p>
- <p>We informally use the term <dfn>g-box</dfn> to refer to a
+ <p>We informally use the term <dfn>RDF source</dfn> to refer to a
persistent yet mutable source or container of
- <a title="RDF graph">RDF graphs</a>. A g-box is a <a>resource</a>
+ <a title="RDF graph">RDF graphs</a>. An RDF source is a <a>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 a g-box. Like all resources, <a>g-boxes</a> may
+ may be considered an RDF source. Like all resources, RDF sources may
be named with <a title="IRI">IRIs</a> and therefore described in
other RDF graphs.</p>
- <p class="issue">“G-box” is a placeholder term. What term should
- we use instead? This is <a href="https://www.w3.org/2011/rdf-wg/track/issues/110">ISSUE-110</a>.</p>
-
<p>Intuitively speaking, changes in the universe of discourse
can be reflected in the following ways:</p>
@@ -357,11 +349,12 @@
<li>Some <a title="property">properties</a> may change over time.
A relationship that holds between two <a title="resource">resources</a>
at one time may not hold at another time.</li>
- <li><a title="g-box">G-boxes</a> may change their state over time.
+ <li><a title="RDF source">RDF sources</a> may change their state
+ over time.
That is, they may contain different <a title="RDF graph">RDF graphs</a>
at different times.</li>
- <li>Some <a title="g-box">g-boxes</a> may, however, be immutable
- snapshots of another g-box, archiving its state at some
+ <li>Some <a title="RDF source">RDF sources</a> may, however, be immutable
+ snapshots of another RDF source, archiving its state at some
point in time.</li>
</ul>
@@ -384,7 +377,7 @@
to hold <a title="RDF triple">triples</a> that involve the graph names.</p>
<p>A common use of <a title="RDF dataset">RDF datasets</a> is to hold
- snapshots of multiple <a title="g-box">g-boxes</a>.</p>
+ snapshots of multiple <a title="RDF source">RDF sources</a>.</p>
</section>
@@ -392,7 +385,9 @@
<h3>Equivalence, Entailment and Inconsistency</h3>
<p class="issue">No Editor's Draft of <em>RDF 1.1 Semantics</em> is
- available yet, and its relationship to this document is not yet
+ available yet
+ (<a href="https://www.w3.org/2011/rdf-wg/track/actions/214">ACTION-214</a>),
+ and its relationship to this document is not yet
entirely clear. Some Semantics-related material may be moved here,
in particular the definition of <dfn title="merge">graph merge</dfn> and
<dfn>subgraph</dfn></li>, and informative
@@ -401,6 +396,12 @@
(excluding any specific vocabulary). This is
<a href="https://www.w3.org/2011/rdf-wg/track/issues/106">ISSUE-106</a>.</p>
+ <p class="issue">The Working Group intends to publish a Working Group
+ Note detailing some of its efforts to define a <strong>formal semantics for
+ RDF datasets</strong>. It should be referenced here when available. This is
+ <a href="http://www.w3.org/2011/rdf-wg/track/actions/209">ACTION-209</a>.
+ </p>
+
<p>An <a>RDF triple</a> encodes a <a title="RDF statement">statement</a>—a
simple <dfn>logical expression</dfn>, or claim about the world.
An <a>RDF graph</a> is the conjunction (logical <em>AND</em>) of
@@ -449,12 +450,6 @@
<a title="inconsistency">inconsistencies</a>, and may make all,
some or no <a title="entailment">entailed</a> information
available to users.</p>
-
- <p class="issue">The Working Group intends to publish a Working Group
- Note detailing some of its efforts to define a formal semantics for
- RDF datasets. This is
- <a href="http://www.w3.org/2011/rdf-wg/track/actions/209">ACTION-209</a>.
- It should be referenced here when available.</p>
</section>
@@ -545,9 +540,7 @@
<p>An <dfn title="IRI"><acronym title="Internationalized Resource Identifier">IRI</acronym></dfn>
(Internationalized Resource Identifier) within an RDF graph
is a Unicode string [[!UNICODE]] that conforms to the syntax
- defined in RFC 3987 [[!RFC3987]]. IRIs are a generalization of
- <dfn title="URI"><acronym title="Uniform Resource Identifier">URI</acronym>s</dfn>
- [[RFC3986]]. Every absolute URI and URL is an IRI.</p>
+ defined in RFC 3987 [[!RFC3987]].</p>
<p>IRIs in the RDF abstract syntax MUST be absolute, and MAY
contain a fragment identifier.</p>
@@ -559,7 +552,12 @@
of [[!RFC3987]]. Further normalization MUST NOT be performed when
comparing IRIs for equality.</p>
- <p class="note">When IRIs are used in operations that are only
+ <div class="note" id="note-iris">
+ <p><strong>URIs and IRIs:</strong>
+ IRIs are a generalization of
+ <dfn title="URI"><acronym title="Uniform Resource Identifier">URI</acronym>s</dfn> [[RFC3986]] that permits a much wider range of Unicode characters.
+ Every absolute URI and URL is an IRI, but not every IRI is an URI.
+ 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>
@@ -568,8 +566,8 @@
characters, %-encoding of octets not allowed in URIs, and
Punycode-encoding of domain names.</p>
- <p class="note">Some
- <a title="concrete RDF syntax">concrete RDF syntaxes</a> permit
+ <p><strong>Relative IRIs:</strong>
+ Some <a title="concrete RDF syntax">concrete RDF syntaxes</a> permit
<dfn title="relative IRI">relative IRIs</dfn> as a convenient shorthand
that allows authoring of documents independently from their final
publishing location. Relative IRIs must be
@@ -579,8 +577,8 @@
if a <a href="http://tools.ietf.org/html/rfc3986#section-5.1">base IRI
can be established</a> [[RFC3986]].</p>
- <div class="note" id="note-iri-interop">
- <p>Interoperability problems can be avoided by minting
+ <p><strong>IRI 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 [[!RFC3987]]. Non-normalized forms that should be avoided
@@ -652,35 +650,17 @@
<a title="datatype IRI">datatype IRIs</a>, and the two
<a title="language tag">language tags</a> (if any)
compare equal, character by character.</p>
-
- <p class="note" id="note-composing-character">Literals in which the
- lexical form begins with a composing character
- (as defined by [[CHARMOD]])
- are allowed however they may cause interoperability problems,
- particularly with XML version 1.1 [[XML11]].</p>
-
- <p class="note" id="note-locale">When using the language tag, care must be
- taken not to confuse language with locale. The language
- tag relates only to human language text. Presentational
- issues should
- be addressed in end-user applications.</p>
-
- <p class="note" id="note-langtag-normalization">The case normalization of
-language tags is part of
- the description of the abstract syntax, and consequently the abstract
- behaviour of RDF applications. It does not constrain an
- RDF implementation to actually normalize the case. Crucially, the result
- of comparing two language tags should not be sensitive to the case of
- the original input.</p>
</section>
<section id="section-blank-nodes">
<h2>Blank Nodes</h2>
- <p class="issue">Re-wordings of this section have been proposed. This is <a href="https://www.w3.org/2011/rdf-wg/track/issues/107">ISSUE-107</a>.</p>
-
- <p class="issue">Proposals for a major re-write of this section have been made, making the notion of a “scope” for blank node identifiers explicit, and defining the concept of a “fresh” blank node. This is ISSUE-XX.</p>
+ <p class="issue">Various proposals have been made for revising
+ this section, ranging from editorial re-wordings to major re-writes
+ that introduce notions of a “scope” for blank node identifiers
+ and define the concept of a “fresh” blank node. This is
+ <a href="https://www.w3.org/2011/rdf-wg/track/issues/107">ISSUE-107</a>.</p>
<p>The <dfn title="blank node">blank nodes</dfn> in an RDF graph
are drawn from an infinite set. This set is disjoint from the set
@@ -744,10 +724,6 @@
<pre>http://example.com/.well-known/genid/d26a2d0e98334696f4ad70a677abc1f6</pre>
- <p class="issue">IETF registration of the <code>genid</code> name is
- currently in progress. This is
- <a href="http://www.w3.org/2011/rdf-wg/track/actions/82">ACTION-82</a>.</p>
-
<p class="note">RFC 5785 [[WELL-KNOWN]] only specifies well-known URIs,
not IRIs. For the purpose of this document, a well-known IRI is any
IRI that results in a well-known URI after IRI-to-URI mapping [[!RFC3987]].</p>
@@ -806,17 +782,19 @@
<p><a title="blank node">Blank nodes</a> MAY be shared between graphs
in an <a>RDF dataset</a>.</p>
- <p class="note" id="note-graph-name">Despite the use of the word “name”
+ <div class="note" id="note-datasets">
+ <p>Despite the use of the word “name”
in “<a>named graph</a>”, the <a>graph name</a> does not formally
<a>denote</a> the graph. It is merely syntactically paired with
the graph. RDF does not place any formal restrictions on what
<a>resource</a> the graph name may denote, nor on the relationship between
that resource and the graph.</p>
- <div class="note" id="note-empty-named-graphs">Some <a>RDF dataset</a>
+ <p>Some <a>RDF dataset</a>
implementations do not track empty <a title="named graph">named graphs</a>.
Therefore, to maximize interoperability, applications should avoid
- ascribing importance to the presence of empty named graphs.</div>
+ ascribing importance to the presence of empty named graphs.</p>
+ </div>
<p class="issue">Should RDF Concepts define any operations on RDF datasets,
such as merge, union, isomorphism, equality, equivalence? Is anything
@@ -853,33 +831,6 @@
of that value. The mapping can be seen as a function
from the lexical space to the value space.</p>
-<div class="note" id="note-datatype-xml-schema">
-<p>When the datatype is defined using XML Schema:
-</p>
-<ul>
-<li>
-All values correspond to some lexical form, either using
-the lexical-to-value mapping of the datatype or if it is a union
-datatype with a lexical mapping associated with one of the member
-datatypes.
-</li>
-<li>
-XML Schema facets remain part of the datatype and are used by the XML
-Schema mechanisms that control the lexical space and the value space;
-however, RDF does not define a standard mechanism to access these facets.</li>
-
- <li>In [[XMLSCHEMA11-1]],
- <a href="http://www.w3.org/TR/xmlschema11-1/#sec-wsnormalization">white space normalization</a>
- occurs during
- <a href="http://www.w3.org/TR/xmlschema11-1/#key-vn">validation</a>
- according to the value of the
- <a href="http://www.w3.org/TR/xmlschema11-2/#rf-whiteSpace">whiteSpace
- facet</a>. The lexical-to-value mapping used in RDF datatyping
- occurs after this, so that the whiteSpace facet has no
- effect in RDF datatyping.</li>
- </ul>
- </div>
-
<p class="note"><a title="language-tagged string">Language-tagged
strings</a> have the <a>datatype IRI</a>
<code>http://www.w3.org/1999/02/22-rdf-syntax-ns#langString</code>.
@@ -1074,18 +1025,16 @@
</dd>
</dl>
- <p class="note" id="note-html-context">Any language annotation
- (<code>lang="…"</code>) or
+ <p class="note" id="note-html">
+ Any language annotation (<code>lang="…"</code>) or
XML namespaces (<code>xmlns</code>) desired in the HTML content
must be included explicitly in the HTML literal. Relative URLs
in attributes such as <code>href</code> do not have a well-defined
- base URL and are best avoided.</p>
-
- <p class="note">RDF applications may use additional equivalence relations,
+ 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>
-
</section>
<section id="section-XMLLiteral">
@@ -1153,13 +1102,6 @@
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 [[RDF-SYNTAX-GRAMMAR]]).</p>
-
- <p class="note" id="note-xml11">Not all values of this datatype
- are compliant with XML 1.1 [[XML11]]. If compliance
- with XML 1.1 is desired, then only those values that are
-<a href="http://www.w3.org/TR/xml11/#dt-fullnorm">fully
- normalized</a> according to XML 1.1 should be used.</p>
-
</section>
<section id="datatype-maps">
@@ -1227,7 +1169,7 @@
<em>syntactically</em> ill-formed.</li>
</ol>
- <p class="issue">What does it mean when a literal is ill-typed or when something is not in the datatype map? What should an implementation do? Should authors avoid generating such graphs? Should consumers reject it? Is an implementation that rejects ill-formed xsd:dates conforming? This is <a href="https://www.w3.org/2011/rdf-wg/track/issues/109">ISSUE-109</a>.</p>
+ <p class="issue">What does it mean when a literal is ill-typed or when something is not in the datatype map? What should an implementation do? Should authors avoid generating such graphs? Should consumers reject it? Is an implementation that rejects ill-formed xsd:dates conforming? Why is an ill-typed literal not necessarily an inconsistency? This is <a href="https://www.w3.org/2011/rdf-wg/track/issues/109">ISSUE-109</a>.</p>
</section>
@@ -1393,6 +1335,8 @@
<em>RDF 1.1 Concepts and Abstract Syntax</em>.</p>
<ul>
+ <li>2012-11-21: Replaced the placeholder term “g-box” with “<a>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>