--- a/rdf-concepts/index.html Thu Nov 10 00:25:45 2011 +0000
+++ b/rdf-concepts/index.html Thu Nov 10 11:51:33 2011 +0000
@@ -1075,72 +1075,42 @@
<section id="section-fragID" class="informative">
<h2>Fragment Identifiers</h2>
- <p class="issue">This section does not address the case where RDF is
- embedded in other document formats, such as in RDFa or when an RDF/XML
- fragment is embedded in SVG. It has been suggested that this may be
- a general issue for the TAG about the treatment of
- fragment identifiers when one language is embedded in another. This is
- <a href="http://www.w3.org/2011/rdf-wg/track/issues/37">ISSUE-37</a>.</p>
-
- <p class="issue">This section treats the RDF/XML media type as
- canonical for establishing the referent of IRIs that include
- fragment identifier. Today we have many different media types
- that can carry RDF graphs, and HTTP content negotiation is more
- common. Also, the problem addressed in the section
- (context-dependence of fragment identifiers) has to some extent
- gone away when RFC 2396 was replaced by RFC 3986. The latter
- states that the same fragment should be used for the same thing
- in resources that have multiple representations
- (Section 3.5 [[URI]]). This is
- <a href="http://www.w3.org/2011/rdf-wg/track/issues/69">ISSUE-69</a>.</p>
+ <p>RDF uses <a title="IRI">IRIs</a>, which may include
+ <dfn>fragment identifiers</dfn>, as resource identifiers.
+ The semantics of fragment identifiers are
+ <a href="http://tools.ietf.org/html/rfc3986#section-3.5">defined in
+ RFC 3986</a> [[URI]]: 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>RDF uses <a title="IRI">IRIs</a>,
- which may include fragment identifiers, as
- context free identifiers for resources. RFC 2396 states
- that the meaning of a fragment
- identifier depends on the MIME content-type of a document, i.e.
- is context dependent.</p>
- <p>These apparently conflicting views are reconciled by
- considering that an <a>IRI</a> in an RDF graph is treated
- with respect to the MIME type <code>application/rdf+xml</code>
- [[RDF-MIME-TYPE]]. Given an IRI that includes a fragment identifier,
- the fragment identifer identifies the same thing
- that it does in an <code>application/rdf+xml</code> representation of the
- resource identified by the IRI excluding the fragment identifier. Thus:</p>
- <ul>
- <li>we assume that the IRI excluding fragment
- identifier identifies a resource, which is presumed to have
- an RDF representation. So when <code>eg:someurl#frag</code> is used in an RDF
- document, <code>eg:someurl</code> is taken to
- designate some RDF document (even when no such document can
- be retrieved).</li>
- <li><code>eg:someurl#frag</code> means the thing
- that is indicated, according to the rules of the
- <code>application/rdf+xml</code> MIME content-type as
- a “fragment” or “view” of the RDF document at
- <code>eg:someurl</code>. If the document does not
- exist, or cannot be retrieved, or is available only in
- formats other than <code>application/rdf+xml</code>, then exactly what
- that view may be is somewhat undetermined, but that does not
- prevent use of RDF to say things about it.</li>
- <li>the RDF treatment of a fragment identifier allows it to
- indicate a thing that is entirely external to the document,
- or even to the “shared information space” known as the Web.
- That is, it can be a more general idea, like some particular
- car or a mythical Unicorn.</li>
- <li>in this way, an <code>application/rdf+xml</code> document acts as an
- intermediary between some Web retrievable documents (itself,
- at least, also any other Web retrievable IRIs that it may
- use, possibly including schema IRIs and references to other
- RDF documents), and some set of possibly abstract or non-Web
- entities that the RDF may describe.</li>
- </ul>
- <p>This provides a handling of IRIs and their
- denotation that is consistent with the RDF model theory and
- usage, and also with conventional Web behavior. Note that
- nothing here requires that an RDF application be able to
- retrieve any representation of resources identified by the IRIs
- in an RDF graph.</p>
+ <p>This section discusses the handling of fragment identifiers
+ in representations that encode <a title="RDF graph">RDF graphs</a>.</p>
+
+ <p>In RDF-bearing representations of a resource <code><foo></code>,
+ the secondary resource identified by a fragment <code>#bar</code>
+ is the entity denoted by the full IRI <code><foo#bar></code>
+ in the RDF graph.
+ Since IRIs in RDF graphs can denote anything, this can be
+ something external to the representation, or even external
+ to the “shared information space” known as the Web.</p>
+
+ <p>In this way, the RDF representation acts as an intermediary
+ between some web-retrievable document, and some set of possibly
+ non-web or abstract entities that the RDF may describe.</p>
+
+ <p>Primary resources may have multiple representations
+ (a.k.a. content negotiation). Fragments in RDF-bearing representations
+ SHOULD be used consistently 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 a primary resource, then <code>#chapter1</code>
+ SHOULD be taken to denote that same section in all RDF-bearing
+ representations of the same primary resource.</p>
+
+ <p>The same constraint applies when RDF graphs are embedded
+ in non-RDF representations.</p>
</section>
@@ -1172,6 +1142,7 @@
<h2>Changes from RDF 2004</h2>
<ul>
+ <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 IRI <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>2011-08-13: Updated Turtle reference to Turtle FPWD</li>