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2415 lines
95 KiB
2415 lines
95 KiB
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<div class="head">
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<a href="http://www.w3.org/"><img height="48" width="72" alt=
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"W3C" src="http://www.w3.org/Icons/w3c_home" /></a>
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<h1 id="title">Resource Description Framework (RDF):<br />
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Concepts and Abstract Syntax</h1>
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<h2 id="doctype">W3C Working Draft 05 September 2003</h2>
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<dl>
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<dt>This version:</dt>
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<dd><a href=
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"http://www.w3.org/TR/2003/WD-rdf-concepts-20030905/">http://www.w3.org/TR/2003/WD-rdf-concepts-20030905/</a></dd>
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<dt>Latest version:</dt>
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<dd><a href=
|
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"http://www.w3.org/TR/rdf-concepts/">http://www.w3.org/TR/rdf-concepts/</a></dd>
|
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|
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<dt>Previous version:</dt>
|
|
|
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<dd><a href=
|
|
"http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/">http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/</a></dd>
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<dt>Editors:</dt>
|
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<dd><a href="http://www.ninebynine.org/">Graham Klyne</a> (Nine
|
|
by Nine), <<a href=
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"mailto:GK@NineByNine.org">gk@ninebynine.org</a>></dd>
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<dd><a href="http://www-uk.hpl.hp.com/people/jjc/">Jeremy J.
|
|
Carroll</a> (Hewlett Packard Labs), <<a href=
|
|
"mailto:jjc@hpl.hp.com">jjc@hpl.hp.com</a>></dd>
|
|
|
|
<dt>Series editor:</dt>
|
|
|
|
<dd><a href="http://www-uk.hpl.hp.com/people/bwm/">Brian
|
|
McBride</a> (Hewlett Packard Labs) <<a href=
|
|
"mailto:bwm@hplb.hpl.hp.com">bwm@hplb.hpl.hp.com</a>></dd>
|
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</dl>
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<p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"> Copyright</a> © 2003 <a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a href="http://www.lcs.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.org/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <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>, <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-software">software licensing</a> rules apply.</p>
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<hr title="Separator for header" />
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</div>
|
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<h2 class="nonum"><a id="abstract" name=
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"abstract">Abstract</a></h2>
|
|
|
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<p>The Resource Description Framework (RDF) is a framework for
|
|
representing information in the Web.</p>
|
|
<p>RDF Concepts and Abstract Syntax defines an abstract syntax
|
|
on which RDF is based, and which serves to link its concrete
|
|
syntax to its formal semantics. It also includes discussion of
|
|
design goals, key concepts, datatyping, character normalization
|
|
and handling of URI references.</p>
|
|
|
|
<h2 class="nonum">
|
|
<a id="status" name="status">Status of this Document</a>
|
|
</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 W3C publications and the latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/">W3C technical reports index</a> at http://www.w3.org/TR/.</em></p>
|
|
|
|
<p>This is a W3C
|
|
<a href="http://www.w3.org/2003/06/Process-20030618/tr.html#RecsWD">Working Draft</a>
|
|
of the <a href="http://www.w3.org/2001/sw/RDFCore/">RDF Core Working Group</a>
|
|
and has been produced as part of the W3C
|
|
<a href="http://www.w3.org/2001/sw/">Semantic Web Activity</a>
|
|
(<a href="http://www.w3.org/2001/sw/Activity">Activity Statement</a>).</p>
|
|
|
|
<p>
|
|
In response to
|
|
<a href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-14">last call comments</a> on the previous
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/">23 January 2003 working draft</a>, and
|
|
<a href="http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0486">feedback</a> from
|
|
the
|
|
<a href="http://www.w3.org/2001/sw/meetings/tech-200303/">technical plenary</a>,
|
|
discussion of the social meaning of RDF has been struck.
|
|
A second notable change is the simplification
|
|
of <a href="#dfn-typed-literal">typed literals</a> to exclude
|
|
<a href="#dfn-language-identifier">language tags</a>.
|
|
The Working Group particularly seeks feedback on the
|
|
impact of this change on the datatype
|
|
<a href="#section-XMLLiteral">rdf:XMLLiteral</a>.
|
|
Detailed changes from the <a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/">23 January 2003 working draft</a>
|
|
are described in
|
|
the <a href="#section-Revisions">Changes section</a>.
|
|
These are
|
|
<a href="#section-substantive-Revisions">non-trivial changes</a> as approved by the RDF Core WG, and
|
|
<a href="#section-editorial-Revisions">editorial changes</a> made, typically in response to
|
|
last call comments, at the discretion of the editors.</p>
|
|
<p>
|
|
This Working Draft consolidates changes and editorial improvements undertaken in response to
|
|
feedback received during the <a
|
|
href="http://www.w3.org/2003/06/Process-20030618/tr#last-call">Last Call</a> publication
|
|
of the RDFCore specifications which began on 23 January 2003. A list of the Last Call
|
|
issues addressed by the Working Group is
|
|
<a href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/">also available</a>.
|
|
This document has been endorsed by the RDF Core Working Group.
|
|
</p>
|
|
|
|
<p>This document is being released for review by W3C Members and
|
|
other interested parties to encourage feedback and comments,
|
|
especially with regard to how the changes made affect existing
|
|
implementations and content.</p>
|
|
|
|
<p>In conformance with
|
|
<a href="http://www.w3.org/Consortium/Process-20010719/#ipr">W3C policy</a>
|
|
requirements, known patent and
|
|
<acronym title="Intellectual Property Rights">IPR</acronym>
|
|
constraints associated with this Working Draft are detailed on the
|
|
<a href="http://www.w3.org/2001/sw/RDFCore/ipr-statements" rel="disclosure">RDF Core Working Group Patent Disclosure</a> page.</p>
|
|
|
|
<p>Comments on this document are invited and should be sent to the
|
|
public mailing list
|
|
<a href="mailto:www-rdf-comments@w3.org">www-rdf-comments@w3.org</a>.
|
|
An archive of comments is available at
|
|
<a href="http://lists.w3.org/Archives/Public/www-rdf-comments/">http://lists.w3.org/Archives/Public/www-rdf-comments/</a>.
|
|
</p>
|
|
|
|
<p>
|
|
Publication as a Working Draft does not imply endorsement by the W3C 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>
|
|
|
|
|
|
|
|
<div class="toc">
|
|
<h2 class="nonum"><a id="contents" name="contents">Table of
|
|
Contents</a></h2>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline">
|
|
<a href="#section-Introduction"><strong>1.
|
|
Introduction</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href="#section-Structure">1.1
|
|
Structure of this Document</a></li>
|
|
|
|
</ul>
|
|
</li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-Overview"><strong>2. Motivations and Goals</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href="#section-motivation">2.1
|
|
Motivation</a></li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-design-goals">2.2 Design Goals</a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href="#section-simple-data-model">2.2.1 A
|
|
Simple Data Model</a></li>
|
|
|
|
<li class="tocline"><a href="#section-formal-semantics">2.2.2 Formal
|
|
Semantics and Inference</a></li>
|
|
|
|
<li class="tocline"><a href="#section-extensible-vocab">2.2.3
|
|
Extensible URI-based Vocabulary</a></li>
|
|
|
|
<li class="tocline"><a href="#section-xml-serialization">2.2.4
|
|
XML-based Syntax</a></li>
|
|
|
|
<li class="tocline"><a href="#section-use-xsd">2.2.5 Use
|
|
XML Schema Datatypes</a></li>
|
|
|
|
<li class="tocline"><a href="#section-anyone">2.2.6 Anyone
|
|
Can Make Statments About Any Resource</a></li>
|
|
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-Concepts"><strong>3. RDF Concepts</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href="#section-data-model">3.1 Graph
|
|
Data Model</a></li>
|
|
|
|
<li class="tocline"><a href=
|
|
"#section-URI-Vocabulary">3.2 URI-based Vocabulary
|
|
and Node Identification</a></li>
|
|
|
|
<li class="tocline"><a href="#section-Datatypes-intro">3.3
|
|
Datatypes</a></li>
|
|
|
|
<li class="tocline"><a href="#section-Literals">3.4
|
|
Literals</a></li>
|
|
|
|
|
|
<li class="tocline"><a href=
|
|
"#section-SimpleFacts">3.5 RDF Expression of Simple
|
|
Facts</a></li>
|
|
|
|
<li class="tocline"><a href="#section-Entailment">3.6
|
|
Entailment</a></li>
|
|
</ul>
|
|
</li>
|
|
<li class="tocline"><a href="#section-URIspaces"><strong>4. RDF
|
|
Vocabulary URI and Namespace (Normative)</strong></a></li>
|
|
<li class="tocline">
|
|
<a href="#section-Datatypes"><strong>5. Datatypes (Normative)</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href="#section-XMLLiteral">5.1
|
|
XML Content within an RDF Graph</a></li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-Graph-syntax"><strong>6. Abstract
|
|
Syntax (Normative)</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href="#section-triples">6.1 RDF
|
|
Triples</a></li>
|
|
|
|
<li class="tocline"><a href="#section-rdf-graph">6.2 RDF
|
|
Graph</a></li>
|
|
|
|
<li class="tocline"><a href="#section-graph-equality">6.3 Graph
|
|
Equivalence</a></li>
|
|
|
|
<li class="tocline"><a href="#section-Graph-URIref">6.4 RDF
|
|
URI References</a></li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-Graph-Literal">6.5 RDF Literals</a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href=
|
|
"#section-Literal-Equality">6.5.1 Literal
|
|
Equality</a></li>
|
|
|
|
<li class="tocline"><a href=
|
|
"#section-Literal-Value">6.5.2 The Value Corresponding
|
|
to a Typed Literal</a></li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li class="tocline"><a href="#section-blank-nodes">6.6 Blank Nodes</a></li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-fragID"><strong>7. Fragment Identifiers
|
|
</strong></a>
|
|
</li>
|
|
|
|
<li class="tocline"><a href=
|
|
"#section-Acknowledgments"><strong>8.
|
|
Acknowledgments</strong></a></li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-References"><strong>9.
|
|
References</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href=
|
|
"#section-Normative-References">9.1 Normative
|
|
References</a></li>
|
|
|
|
<li class="tocline"><a href=
|
|
"#section-Informative-References">9.2 Informational
|
|
References</a></li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li class="tocline">
|
|
<a href="#section-Revisions"><strong>A: Revisions since last-call draft 23 January 2003</strong></a>
|
|
|
|
<ul class="toc">
|
|
<li class="tocline"><a href=
|
|
"#section-substantive-Revisions">A.1: Non-Editorial Revisions</a></li>
|
|
|
|
<li class="tocline"><a href=
|
|
"#section-editorial-Revisions">A.2: Editorial Revisions</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
|
|
</div>
|
|
<hr />
|
|
|
|
<h2><a id="section-Introduction" name="section-Introduction">1.
|
|
Introduction</a></h2>
|
|
|
|
<p>The Resource Description Framework (RDF) is a framework for
|
|
representing information in the Web.</p>
|
|
|
|
<p>This document defines an abstract syntax on which RDF is based,
|
|
and which serves to link its concrete syntax to its formal
|
|
semantics.
|
|
This abstract syntax is quite distinct from XML's tree-based infoset [<a
|
|
href="#ref-xml-infoset">XML-INFOSET</a>]. It also includes discussion of design goals,
|
|
key concepts, datatyping, character normalization
|
|
and handling of URI references.</p>
|
|
|
|
<p>Normative documentation of RDF falls into the following
|
|
areas:</p>
|
|
|
|
<ul>
|
|
<li>XML serialization syntax [<a href=
|
|
"#ref-rdf-syntax">RDF-SYNTAX</a>],</li>
|
|
|
|
<li>formal semantics [<a href=
|
|
"#ref-rdf-semantics">RDF-SEMANTICS</a>], and</li>
|
|
|
|
<li>this document, (sections 4, 5 and 6).</li>
|
|
</ul>
|
|
|
|
<p>Within this document, normative sections are explicitly labelled as such.
|
|
Explicit notes are informative.</p>
|
|
|
|
<p>The framework is designed so that vocabularies can be layered.
|
|
The RDF and RDF vocabulary definition (RDF schema)
|
|
languages
|
|
[<a href="#ref-rdf-vocabulary">RDF-VOCABULARY</a>] are the first
|
|
such vocabularies.
|
|
|
|
Others (cf. OWL [<a href="#ref-owl">OWL</a>] and
|
|
the applications mentioned in the primer
|
|
[<a href=
|
|
"#ref-rdf-primer">RDF-PRIMER</a>]) are in development.</p>
|
|
|
|
<h3><a id="section-Structure" name="section-Structure">1.1
|
|
Structure of this Document</a></h3>
|
|
|
|
<p>In <a href="#section-Overview">section 2</a>,
|
|
the background rationale and design goals
|
|
are introduced.
|
|
Key concepts follow in <a href="#section-Concepts">section 3</a>.
|
|
<a href="#section-URIspaces">Section 4</a> discusses URI references
|
|
reserved for use by RDF.
|
|
</p>
|
|
|
|
|
|
<p><a href="#section-Datatypes">Section 5</a> discusses datatypes.
|
|
XML content of
|
|
literals is described in <a href="#section-XMLLiteral">section
|
|
5.1</a>, and the abstract syntax is defined in <a href=
|
|
"#section-Graph-syntax">section 6</a> of this document.</p>
|
|
|
|
<p><a href="#section-fragID">Section 7</a> discusses the role of fragment
|
|
identifiers in URI references used with RDF.</p>
|
|
|
|
<h2><a id="section-Overview" name="section-Overview">2. Motivations and Goals</a></h2>
|
|
|
|
<p>RDF has an abstract syntax that reflects a simple graph-based
|
|
data model, and formal semantics with a rigorously defined notion
|
|
of entailment providing a basis for well founded deductions in RDF
|
|
data.</p>
|
|
|
|
<h3><a id="section-motivation" name="section-motivation">2.1 Motivation</a></h3>
|
|
|
|
<p>The development of RDF has been motivated by the following uses,
|
|
among others:</p>
|
|
|
|
<ul>
|
|
<li>Web metadata: providing information about Web resources and
|
|
the systems that use them (e.g. content rating, capability
|
|
descriptions, privacy preferences, etc.)</li>
|
|
|
|
<li>Applications that require open rather than constrained
|
|
information models (e.g. scheduling activities, describing
|
|
organizational processes, annotation of Web resources, etc.)</li>
|
|
|
|
<li>To do for machine processable information (application data)
|
|
what the World Wide Web has done for hypertext: to allow data to
|
|
be processed outside the particular environment in which it was
|
|
created, in a fashion that can work at Internet scale.</li>
|
|
|
|
<li>Interworking among applications: combining data from several
|
|
applications to arrive at new information.</li>
|
|
|
|
<li>Automated processing of Web information by software agents:
|
|
the Web is moving from having just human-readable information to
|
|
being a world-wide network of cooperating processes. RDF provides
|
|
a world-wide lingua franca for these processes.</li>
|
|
</ul>
|
|
|
|
<p>RDF is designed to represent information in a minimally
|
|
constraining, flexible way. It can be used in isolated
|
|
applications, where individually designed formats
|
|
might be more direct and easily understood, but RDF's generality offers greater value from
|
|
sharing. The value of information thus increases as it becomes
|
|
accessible to more applications across the entire Internet.</p>
|
|
|
|
<h3><a id="section-design-goals" name="section-design-goals">2.2 Design Goals</a></h3>
|
|
|
|
<p>The design of RDF is intended to meet the following goals:</p>
|
|
|
|
<ul>
|
|
<li>having a simple data model</li>
|
|
<li>having formal semantics and provable inference</li>
|
|
<li>using an extensible URI-based vocabulary</li>
|
|
<li>using an XML-based syntax</li>
|
|
<li>supporting use of XML schema datatypes</li>
|
|
<li>allowing anyone to make statements about any
|
|
resource</li>
|
|
</ul>
|
|
|
|
<h4><a id="section-simple-data-model" name="section-simple-data-model">2.2.1 A Simple Data
|
|
Model</a></h4>
|
|
|
|
<p>RDF has a simple data model that is easy for applications to
|
|
process and manipulate. The data model is independent of any
|
|
specific serialization syntax.</p>
|
|
|
|
<p class="note"><strong>Note:</strong> the term "model" used here in "data model" has a
|
|
completely different sense to its use in the term "model theory".
|
|
See [<a href=
|
|
"#ref-rdf-semantics">RDF-SEMANTICS</a>]
|
|
for more information about "model
|
|
theory" as used in the literature of mathematics and logic.</p>
|
|
|
|
<h4><a id="section-formal-semantics" name="section-formal-semantics">2.2.2 Formal Semantics
|
|
and Inference</a></h4>
|
|
|
|
<p>RDF has a formal semantics which provides a dependable basis for
|
|
reasoning about the meaning of an RDF expression. In particular, it
|
|
supports rigorously defined notions of entailment which provide a
|
|
basis for defining reliable rules of inference in RDF data.</p>
|
|
|
|
<h4><a id="section-extensible-vocab" name="section-extensible-vocab">2.2.3 Extensible
|
|
URI-based Vocabulary</a></h4>
|
|
|
|
<p>The vocabulary is fully extensible, being based on URIs with
|
|
optional fragment identifiers (<cite>URI references</cite>, or
|
|
<cite>URIrefs</cite>). URI references are used for naming all kinds
|
|
of things in RDF.</p>
|
|
|
|
<p>The other kind of value that appears in RDF data is a
|
|
literal.</p>
|
|
|
|
<h4><a id="section-xml-serialization" name="section-xml-serialization">2.2.4 XML-based
|
|
Syntax</a></h4>
|
|
|
|
<p>RDF has a recommended XML serialization form [<a href=
|
|
"#ref-rdf-syntax">RDF-SYNTAX</a>], which can be used to encode the
|
|
data model for exchange of information among applications.</p>
|
|
|
|
<h4><a id="section-use-xsd" name="section-use-xsd">2.2.5 Use XML Schema
|
|
Datatypes</a></h4>
|
|
|
|
<p>RDF can use values represented according to XML schema datatypes
|
|
[<a href="#ref-xml-schema2">XML-SCHEMA2</a>], thus assisting the
|
|
exchange of information between RDF and other XML applications.</p>
|
|
|
|
<h4><a id="section-anyone" name="section-anyone">2.2.6 Anyone Can Make
|
|
Statements About Any Resource</a></h4>
|
|
|
|
<p>To facilitate operation at Internet scale, RDF is an
|
|
open-world framework that allows anyone to make statements
|
|
about any resource.</p>
|
|
<p>In general, it is not assumed that complete information
|
|
about any resource is available. RDF does not prevent anyone
|
|
from making assertions that are nonsensical or inconsistent
|
|
with other statements, or the world as people see it. Designers
|
|
of applications that use RDF should be aware of this and may
|
|
design their applications to tolerate incomplete or
|
|
inconsistent sources of information.</p>
|
|
|
|
<!-- here -->
|
|
<h2><a id="section-Concepts" name="section-Concepts">3. RDF
|
|
Concepts</a></h2>
|
|
|
|
<p>RDF uses the following key concepts:</p>
|
|
|
|
<ul>
|
|
<li>Graph data model</li>
|
|
|
|
<li>URI-based vocabulary</li>
|
|
|
|
<li>Datatypes</li>
|
|
|
|
<li>Literals</li>
|
|
|
|
<li>XML serialization syntax</li>
|
|
|
|
<li>Expression of simple facts</li>
|
|
|
|
<li>Entailment</li>
|
|
</ul>
|
|
|
|
<h3><a id="section-data-model" name="section-data-model">3.1 Graph Data
|
|
Model</a></h3>
|
|
|
|
<p>The underlying structure of any expression in RDF is a
|
|
collection of triples, each consisting of a subject, a
|
|
predicate and an object. A set of such triples is called an RDF
|
|
graph (defined more formally in
|
|
<a href="#section-Graph-syntax">section 6</a>). This can be
|
|
illustrated by a node and directed-arc diagram, in which each
|
|
triple is represented as a node-arc-node link (hence the term
|
|
"graph").</p>
|
|
<div class="block">
|
|
<p><img src="Graph-ex.gif"
|
|
alt="image of the RDF triple comprising (subject, predicate, object)"
|
|
height="72" width="361" /></p>
|
|
</div>
|
|
<p>Each triple represents a statement of a relationship between
|
|
the things denoted by the nodes that it links. Each triple has
|
|
three parts:</p>
|
|
<ol>
|
|
<li>a <a href="#dfn-subject">subject</a>,</li>
|
|
<li>an <a href="#dfn-object">object</a>, and</li>
|
|
<li>a <a href="#dfn-predicate">predicate</a> (also called a
|
|
<a href="#dfn-property">property</a>) that denotes a
|
|
relationship.</li>
|
|
</ol>
|
|
<p>The direction of the arc is significant: it always points
|
|
toward the object.</p>
|
|
<p>The <a href="#section-Graph-Node">nodes</a> of an RDF graph
|
|
are its subjects and objects.</p>
|
|
<p>The assertion of an RDF triple says that some relationship,
|
|
indicated by the predicate, holds between the things denoted by
|
|
subject and object of the triple. The assertion of an RDF graph
|
|
amounts to asserting all the triples in it, so the meaning of
|
|
an RDF graph is the conjunction (logical AND) of the statements
|
|
corresponding to all the triples it contains. A formal account
|
|
of the meaning of RDF graphs is given in [<a
|
|
href="#ref-rdf-semantics">RDF-SEMANTICS</a>].</p>
|
|
|
|
|
|
<h3><a id="section-URI-Vocabulary" name=
|
|
"section-URI-Vocabulary">3.2 URI-based Vocabulary and Node
|
|
Identification</a></h3>
|
|
|
|
|
|
<p>A node may be a URI with optional fragment identifier (<a
|
|
href="#dfn-URI-reference">URI reference</a>, or <dfn><a
|
|
id="dfn-URIref" name="dfn-URIref">URIref</a></dfn>), a literal,
|
|
or blank (having no separate form of identification).
|
|
Properties are <cite>URI references</cite>. (See [<a
|
|
href="#ref-uris">URI</a>], section 4, for a description of URI
|
|
reference forms, noting that relative URIs are not used in an
|
|
RDF graph. See also <a href="#section-Graph-URIref">section
|
|
6.4</a>.)</p>
|
|
<p>A URI reference or literal used as a node identifies what
|
|
that node represents. A URI reference used as a predicate
|
|
identifies a relationship between the things represented by the nodes it connects. A
|
|
predicate URI reference may also be a node in the graph.</p>
|
|
<p>A <a href="#dfn-blank-node">blank node</a> is a node that is
|
|
not a URI reference or a literal. In the RDF abstract syntax, a
|
|
blank node is just a unique node that can be used in one or
|
|
more RDF statements, and has no globally distinguishing
|
|
identity.</p>
|
|
<p>A convention used by some linear representations of an RDF
|
|
graph to allow several statements to reference the same
|
|
unidentified resource is to use a <dfn><a
|
|
id="dfn-blank-node-id" name="dfn-blank-node-id">blank node
|
|
identifier</a></dfn>, which is a local identifier that can be
|
|
distinguished from all URIs and literals. When graphs are
|
|
merged, their blank nodes must be kept distinct if meaning is
|
|
to be preserved; this may call for re-allocation of blank node
|
|
identifiers. Note that such blank node identifiers are not part
|
|
of the RDF abstract syntax, and the representation of triples
|
|
containing blank nodes is entirely dependent on the particular
|
|
concrete syntax used.</p>
|
|
|
|
|
|
<h3><a name="section-Datatypes-intro" id="section-Datatypes-intro">3.3
|
|
Datatypes</a></h3>
|
|
|
|
<p>Datatypes are used by RDF in the representation of values such
|
|
as integers, floating point numbers and dates.</p>
|
|
|
|
<p>
|
|
A datatype consists of a lexical space, a value space and a lexical-to-value
|
|
mapping, see <a href="#section-Datatypes">section 5</a>.
|
|
</p>
|
|
|
|
<p>For example, the lexical-to-value mapping for the XML Schema datatype
|
|
<var>xsd:boolean</var>, where each member of the value space
|
|
(represented here as 'T' and 'F') has two lexical representations,
|
|
is as follows:</p>
|
|
|
|
<table border="1" cellpadding="5" summary=
|
|
"A table detailing the xsd:boolean datatype.">
|
|
<tr>
|
|
<th align="left">Value Space</th>
|
|
|
|
<td>{T, F}</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<th align="left">Lexical Space</th>
|
|
|
|
<td>{"0", "1", "true", "false"}</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<th align="left">Lexical-to-Value Mapping</th>
|
|
|
|
<td>{<"true", T>, <"1", T>, <"0", F>,
|
|
<"false", F>}</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>RDF predefines just one datatype <a href=
|
|
"#dfn-rdf-XMLLiteral" class="code">rdf:XMLLiteral</a>, used for
|
|
embedding XML in RDF (see <a href="#section-XMLLiteral">section
|
|
5.1</a>).</p>
|
|
|
|
<p>There is no built-in concept of numbers or dates or other common
|
|
values. Rather, RDF defers to datatypes that are defined
|
|
separately, and identified with URI references.
|
|
The predefined XML Schema
|
|
datatypes [<a href="#ref-xml-schema2">XML-SCHEMA2</a>] are expected
|
|
to be widely used for this purpose.</p>
|
|
|
|
|
|
<p>RDF provides no mechanism for defining new datatypes. XML Schema
|
|
Datatypes [<a href="#ref-xml-schema2">XML-SCHEMA2</a>] provides an
|
|
extensibility framework suitable for defining new datatypes for use
|
|
in RDF.</p>
|
|
|
|
<h3><a name="section-Literals" id="section-Literals">3.4
|
|
Literals</a></h3>
|
|
|
|
<p>Literals are used to identify values such as numbers and dates
|
|
by means of a lexical representation. Anything represented by a
|
|
literal could also be represented by a URI, but it is often more
|
|
convenient or intuitive to use literals.</p>
|
|
|
|
<p>A literal may be the object of an RDF statement, but not the
|
|
subject or the predicate.</p>
|
|
|
|
<p>Literals may be <cite>plain</cite> or <cite>typed</cite> :</p>
|
|
|
|
<ul>
|
|
<li>A <a href="#dfn-plain-literal" >plain literal</a> is a string combined
|
|
with an optional language tag. This may be used for
|
|
plain text in a natural language. As recommended in the RDF
|
|
formal semantics [<a href=
|
|
"#ref-rdf-semantics">RDF-SEMANTICS</a>], these plain literals are
|
|
self-denoting.</li>
|
|
|
|
|
|
|
|
<li>A <a href="#dfn-typed-literal" >typed literal</a> is a string combined with a
|
|
datatype URI. It denotes the
|
|
member of the identified datatype's value space obtained by
|
|
applying the lexical-to-value mapping to the literal string.</li>
|
|
</ul>
|
|
|
|
<p>Continuing the example from <a href="#section-Datatypes-intro">section
|
|
3.3</a>, the typed literals that can be defined using the XML
|
|
Schema datatype <var>xsd:boolean</var> are:</p>
|
|
|
|
<table border="1" cellpadding="5" summary=
|
|
"This table lists the literals of type xsd:boolean.">
|
|
<tr>
|
|
<th>Typed Literal</th>
|
|
|
|
<th>Lexical-to-Value Mapping</th>
|
|
|
|
<th>Value</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="center"><xsd:boolean, "true"></td>
|
|
|
|
<td align="center"><"true", T></td>
|
|
|
|
<td align="center">T</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="center"><xsd:boolean, "1"></td>
|
|
|
|
<td align="center"><"1", T></td>
|
|
|
|
<td align="center">T</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="center"><xsd:boolean, "false"></td>
|
|
|
|
<td align="center"><"false", F></td>
|
|
|
|
<td align="center">F</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="center"><xsd:boolean, "0"></td>
|
|
|
|
<td align="center"><"0", F></td>
|
|
|
|
<td align="center">F</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>For text that may contain
|
|
markup, use typed literals
|
|
with type <a href="#section-XMLLiteral">rdf:XMLLiteral</a>.
|
|
If language annotation is required,
|
|
it must be explicitly included as markup, usually by means of an
|
|
<code>xml:lang</code> attribute.
|
|
<a href="#ref-xhtml">[XHTML]</a> may be included within RDF
|
|
in this way. Sometimes, in this latter case,
|
|
an additional <code>span</code> or <code>div</code>
|
|
element is needed to carry an
|
|
<code>xml:lang</code> or <code>lang</code> attribute.
|
|
</p>
|
|
|
|
|
|
<h3><a id="section-SimpleFacts" name="section-SimpleFacts">3.5
|
|
RDF Expression of Simple Facts</a></h3>
|
|
|
|
|
|
<p>Some simple facts indicate a relationship between
|
|
two things.
|
|
Such a fact may be represented as an RDF triple in which the predicate
|
|
names the relationship, and the subject and object denote the two things.
|
|
|
|
|
|
A familiar representation of such a fact might be
|
|
as a row in a table in a relational database. The table has
|
|
two columns, corresponding to the subject and the object of the
|
|
RDF triple.
|
|
The name of the table corresponds to the predicate
|
|
of the RDF triple. A further familiar representation may be as a
|
|
two place predicate
|
|
in first order logic.</p>
|
|
|
|
<p>
|
|
Relational databases permit a table to have an arbitrary number of columns,
|
|
a row of which expresses information corresponding to a predicate in first
|
|
order logic with an arbitrary number of places. Such a row, or predicate,
|
|
has to be decomposed for representation as RDF triples. A simple form of
|
|
decomposition introduces a new blank node, corresponding to the row, and a
|
|
new triple is introduced for each cell in the row. The subject of each
|
|
triple is the new blank node, the predicate corresponds to the column name,
|
|
and object corresponds to the value in the cell. The new blank node may
|
|
also have an <span class="code">rdf:type</span> property whose value corresponds
|
|
to the table name.
|
|
</p>
|
|
|
|
<p>As an example, consider Figure 6 from the
|
|
[<a href=
|
|
"#ref-rdf-primer">RDF-PRIMER</a>]:
|
|
|
|
</p>
|
|
|
|
|
|
<div class="figure">
|
|
<img src="fig6may19" alt=
|
|
"Using a Blank Node" width="100%" /><br />
|
|
RDF Primer Figure 6: Using a Blank Node
|
|
</div>
|
|
|
|
|
|
<p>
|
|
This information might correspond to a row in a table <span class="code">"STAFFADDRESSES"</span>,
|
|
with a primary key
|
|
<span class="code">STAFFID</span>,
|
|
and additional columns
|
|
<span class="code">STREET</span>,
|
|
<span class="code">STATE</span>,
|
|
<span class="code">CITY</span> and
|
|
<span class="code">POSTALCODE</span>.
|
|
</p>
|
|
|
|
<p>
|
|
Thus, a more complex fact is expressed in RDF using a
|
|
conjunction (logical-AND) of simple binary relationships. RDF does not
|
|
provide means to express negation (NOT) or disjunction (OR). </p>
|
|
|
|
<p>Through its use of extensible URI-based vocabularies, RDF
|
|
provides for expression of facts about arbitrary subjects; i.e.
|
|
assertions of named properties about specific named things. A URI
|
|
can be constructed for any thing that can be named, so RDF facts
|
|
can be about any such things. <!--
|
|
And, as noted above, RDF also
|
|
provides for expression of assertions about unnamed things, which
|
|
may be fully identifiable in terms of such assertions [<a
|
|
href="#ref-tap-rbd">TAP-RBD</a>].
|
|
-->
|
|
</p>
|
|
|
|
|
|
<h3><a id="section-Entailment" name="section-Entailment">3.6
|
|
Entailment</a></h3>
|
|
|
|
<p>The ideas on meaning and inference in RDF are underpinned by the
|
|
formal concept of <a href="http://www.w3.org/TR/rdf-mt/#entail">
|
|
<cite>entailment</cite></a>, as
|
|
discussed in the RDF
|
|
semantics document [<a href=
|
|
"#ref-rdf-semantics">RDF-SEMANTICS</a>].
|
|
In brief, an RDF expression A is said to
|
|
<dfn>entail</dfn> another RDF expression B if every possible
|
|
arrangement of things in the world that makes A true also makes B
|
|
true. On this basis, if the truth of A is presumed or demonstrated
|
|
then the truth of B can be inferred .
|
|
</p>
|
|
|
|
|
|
<h2><a id="section-URIspaces" name="section-URIspaces">4. RDF
|
|
Vocabulary URI and Namespace (Normative)</a></h2>
|
|
|
|
<p>
|
|
|
|
RDF uses URI references to identify resources and properties. Certain
|
|
URI references are given specific meaning by RDF. Specifically, URI
|
|
references with the following leading substring are defined by the RDF
|
|
specifications:
|
|
|
|
</p>
|
|
<ul>
|
|
<li><span
|
|
class="code">http://www.w3.org/1999/02/22-rdf-syntax-ns#</span>
|
|
(conventionally associated with namespace prefix <span
|
|
class="code">rdf:</span>)</li>
|
|
<!--
|
|
<li><span
|
|
class="code">http://www.w3.org/2000/01/rdf-schema#</span>
|
|
(conventionally associated with namespace prefix <span
|
|
class="code">rdfs:</span>)</li>
|
|
-->
|
|
</ul>
|
|
<p>Used with the RDF/XML serialization, this URI prefix
|
|
string corresponds to XML namespace names [<a
|
|
href="#ref-namespaces">XML-NS</a>] associated with the RDF
|
|
vocabulary terms.</p>
|
|
<div class="note">
|
|
<p><strong>Note:</strong> this namespace name is the same
|
|
as that used in the earlier RDF recommendation [<a
|
|
href="#ref-rdf-ms">RDF-MS</a>].</p>
|
|
</div>
|
|
<p>Vocabulary terms in the <span class="code">rdf:</span>
|
|
namespace are listed in <a
|
|
href="http://www.w3.org/TR/rdf-syntax-grammar/#section-Namespace">
|
|
section 5.1</a> of the RDF syntax specification [<a
|
|
href="#ref-rdf-syntax">RDF-SYNTAX</a>]. Some of these terms are
|
|
defined by the RDF specifications to denote specific concepts.
|
|
Others have syntactic purpose (e.g. rdf:ID is part of
|
|
the RDF/XML syntax).</p>
|
|
<!--
|
|
<p>Vocabulary terms defined in the <span
|
|
class="code">rdfs:</span> namespace are defined in the RDF
|
|
schema vocabulary specification [<a
|
|
href="#ref-rdf-vocabulary">RDF-VOCABULARY</a>].</p>
|
|
-->
|
|
|
|
<h2><a name="section-Datatypes" id="section-Datatypes">5.
|
|
Datatypes (Normative)</a></h2>
|
|
|
|
<p>
|
|
The datatype abstraction used in RDF is compatible with
|
|
the abstraction used in
|
|
XML Schema Part 2:
|
|
Datatypes [<a href="#ref-xml-schema2">XML-SCHEMA2</a>].</p>
|
|
<p>
|
|
A datatype consists of a lexical space, a value space and a lexical-to-value
|
|
mapping.
|
|
</p>
|
|
<p>The <dfn><a id="dfn-lexical-space"
|
|
name="dfn-lexical-space">lexical space</a></dfn> of a datatype is a set of Unicode [<a
|
|
href="#ref-unicode">UNICODE</a>] strings.</p>
|
|
<p>
|
|
The <dfn><a id="dfn-lexical-to-value-mapping" name=
|
|
"dfn-lexical-to-value-mapping">lexical-to-value mapping</a></dfn> of a datatype is a set of pairs whose
|
|
first element belongs to
|
|
the <dfn><a href="#dfn-lexical-space">lexical space</a></dfn> of the datatype,
|
|
and the second element belongs to the
|
|
<dfn><a id="dfn-value-space"
|
|
name="dfn-value-space">value space</a></dfn> of the datatype:
|
|
</p>
|
|
<ul>
|
|
<li>
|
|
Each member of the lexical space is paired with (maps to) exactly one member
|
|
of the value space.
|
|
</li>
|
|
<li>
|
|
Each member of the value space may be paired with any number (including
|
|
zero) of members of the lexical space (lexical representations for that
|
|
value).
|
|
</li>
|
|
</ul>
|
|
<p>
|
|
A datatype is identified by one or more URI references.
|
|
</p>
|
|
<p>
|
|
RDF may be used with any datatype definition that conforms to this
|
|
abstraction, even if not defined in terms of XML Schema.
|
|
</p>
|
|
<p>Certain XML Schema built-in datatypes are not suitable for use
|
|
within RDF. For example, the
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#QName">QName</a>
|
|
datatype requires a namespace declaration to be in scope during
|
|
the mapping, and is not recommended for use in RDF.
|
|
[<a href=
|
|
"#ref-rdf-semantics">RDF-SEMANTICS</a>] contains
|
|
a
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-mt-20030905/#dtype_interp">more detailed discussion</a>
|
|
of specific XML Schema built-in datatypes. </p>
|
|
|
|
<div class="note">
|
|
<p><strong>Note:</strong> 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 [<a href="#ref-xml-schema1">XML-SCHEMA1</a>],
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#section-White-Space-Normalization-during-Validation">
|
|
white space normalization</a> occurs
|
|
during
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#key-vn">validation</a>
|
|
according to the value of the
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/datatypes.html#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>
|
|
<!--
|
|
<p><a name="whiteSpace-impl-note" id="whiteSpace-impl-note"> </a>
|
|
<strong>Implementation Note: (normative)</strong>
|
|
|
|
In [<a href="#ref-xml-schema1">XML-SCHEMA1</a>],
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#section-White-Space-Normalization-during-Validation">
|
|
white space normalization</a> occurs during <a href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#key-vn">validation</a>
|
|
according to the value of the
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/datatypes.html#rf-whiteSpace">whiteSpace
|
|
facet</a>.
|
|
The lexical-to-value
|
|
mapping used in RDF datatyping occurs after this, so that in RDF
|
|
datatyping the whiteSpace facet formally has no effect. However, in line
|
|
with the principle of being liberal with what is accepted and strict
|
|
with what is produced:
|
|
</p>
|
|
<ul>
|
|
<li>During input processing of XML Schema Datatypes within RDF, software
|
|
MAY apply the appropriate whitespace normalization immediatly before the
|
|
lexical to value mapping, and MAY produce a warning if any whitespace is
|
|
changed in this normalization.
|
|
</li>
|
|
<li>
|
|
Software generating RDF data SHOULD produce lexical forms which do not
|
|
require whitespace processing.</li>
|
|
</ul>
|
|
<p>
|
|
(The keywords MAY and SHOULD are defined in [<a href="#ref-keywords">KEYWORDS</a>],)
|
|
</p>
|
|
-->
|
|
|
|
|
|
</div>
|
|
|
|
<h3><a id="section-XMLLiteral" name="section-XMLLiteral">5.1 XML
|
|
Content within an RDF Graph</a></h3>
|
|
|
|
<p>RDF provides for XML content as a possible literal value. This
|
|
typically originates from the use of
|
|
<span class="code">rdf:parseType="Literal"</span> in the RDF/XML Syntax [<a
|
|
href="#ref-rdf-syntax">RDF-SYNTAX</a>].</p>
|
|
|
|
<p>Such content is indicated in an RDF graph using a typed literal
|
|
whose datatype is a special built-in datatype
|
|
<dfn><a id="dfn-rdf-XMLLiteral" name= "dfn-rdf-XMLLiteral" class="code">rdf:XMLLiteral</a></dfn>,
|
|
defined as follows.</p>
|
|
|
|
<!--
|
|
<p>As part of the definition of this datatype, an ancillary
|
|
definition is used.</p>
|
|
|
|
<p>The <em>XML document corresponding to</em> a pair <var>( str,
|
|
lang )</var> is formed as follows:</p>
|
|
|
|
<div class="block">
|
|
<p>Concatenate the five strings:</p>
|
|
|
|
<ol>
|
|
<li><span class="code">"<rdf-wrapper xml:lang='"</span></li>
|
|
|
|
<li><var>lang</var></li>
|
|
|
|
<li><span class="code">"'>"</span></li>
|
|
|
|
<li><var>str</var></li>
|
|
|
|
<li><span class="code">"</rdf-wrapper>"</span></li>
|
|
</ol>
|
|
|
|
<p>Encode the resulting Unicode string in UTF-8 to form the
|
|
corresponding XML document.</p>
|
|
|
|
<p>No escaping is applied. The choice of <span class="code">rdf-wrapper</span>
|
|
is fixed but arbitrary.</p>
|
|
</div>
|
|
|
|
<p>The <em>XML document corresponding to</em> a string
|
|
<var>str</var> is formed as the XML document corresponding to the
|
|
pair <var>(str, "")</var>.</p>
|
|
-->
|
|
|
|
<dl>
|
|
<dt><a name="XMLLiteral-uri" id="XMLLiteral-uri">A URI reference for
|
|
identifying this datatype</a></dt>
|
|
|
|
<dd>is
|
|
<span class="code">http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral</span>.</dd>
|
|
|
|
|
|
|
|
|
|
<dt><a name="XMLLiteral-lexical-space" id="XMLLiteral-lexical-space">The lexical space</a></dt>
|
|
|
|
<dd>is the set of all
|
|
strings:
|
|
<ul>
|
|
<li>which are well-balanced, self-contained
|
|
<a href="http://www.w3.org/TR/2000/REC-xml-20001006#NT-content">
|
|
XML content</a>
|
|
[<a href="#ref-xml">XML</a>];
|
|
</li>
|
|
<li>for which encoding as UTF-8
|
|
[<a href="#ref-rfc-2279">RFC 2279</a>] yields
|
|
<a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/#def-exclusive-canonical-XML">
|
|
exclusive
|
|
Canonical XML </a> (with comments, with empty
|
|
<a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/#def-InclusiveNamespaces-PrefixList">
|
|
InclusiveNamespaces PrefixList
|
|
</a>) <a href="#ref-xml-xc14n">[XML-XC14N]</a>;
|
|
</li>
|
|
<li>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> <a href="#ref-namespaces">[XML-NS]</a></li>
|
|
</ul>
|
|
</dd>
|
|
|
|
|
|
<dt><a name="XMLLiteral-value-space" id="XMLLiteral-value-space">The value space</a></dt>
|
|
|
|
<dd>is a set of entities, called XML values, which is:
|
|
<ul>
|
|
<li>disjoint from the lexical space;</li>
|
|
<li>disjoint from the value space of any XML schema datatype
|
|
[<a href="#ref-xml-schema2">XML-SCHEMA2</a>];</li>
|
|
|
|
<li>disjoint from the set of Unicode character strings [<a
|
|
href="#ref-unicode">UNICODE</a>] strings;</li>
|
|
<li>and in 1:1 correspondence with the lexical space.</li>
|
|
</ul>
|
|
</dd>
|
|
|
|
<dt><a name="XMLLiteral-mapping" id="XMLLiteral-mapping">The lexical-to-value mapping</a></dt>
|
|
|
|
<dd>
|
|
is a one-one mapping from the lexical space onto the value space,
|
|
i.e. it is both injective and surjective.
|
|
</dd>
|
|
|
|
|
|
|
|
</dl>
|
|
|
|
|
|
<p class="note"><strong>Note:</strong> Not all values of this datatype are compliant
|
|
with XML 1.1 [<a href="#ref-xml-1-1">XML 1.1</a>]. If compliance
|
|
with XML 1.1 is desired, then only those values that are
|
|
<a href="http://www.w3.org/TR/2002/CR-xml11-20021015/#sec2.13">fully
|
|
normalized</a> according to XML 1.1 should be used.</p>
|
|
|
|
<p class="note"><strong>Note:</strong> XML values can be thought of as the
|
|
[<a href="#ref-xml-infoset">XML-INFOSET</a>] or the
|
|
[<a href="#ref-xpath">XPATH</a>]
|
|
nodeset corresponding to the lexical form, with an appropriate equality
|
|
function.</p>
|
|
|
|
<p class="note"><strong>Note:</strong> RDF applications may use additional equivalence relations, such as
|
|
that which relates an
|
|
<a href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#string"><code>xsd:string</code></a>
|
|
|
|
with an <code>rdf:XMLLiteral</code> corresponding to
|
|
a single text node of the same string.</p>
|
|
|
|
|
|
|
|
<h2><a id="section-Graph-syntax" name="section-Graph-syntax">6.
|
|
Abstract Syntax (Normative)</a></h2>
|
|
|
|
|
|
<p>This section defines the RDF abstract syntax. The RDF abstract
|
|
syntax is a set of triples, called the RDF graph.</p>
|
|
|
|
<p>This section also defines equivalence between RDF graphs. A
|
|
definition of equivalence is needed to support the RDF Test Cases [<a
|
|
href="#ref-rdf-tests">RDF-TESTS</a>] specification.</p>
|
|
|
|
<div class="note">
|
|
<p><a name="implementation-note" id="implementation-note"><strong>Implementation Note:</strong></a>
|
|
This <em>abstract</em> syntax is the
|
|
syntax over which the formal semantics are defined.
|
|
Implementations are free to represent RDF graphs in
|
|
any other equivalent form. As an example:
|
|
in an RDF graph,
|
|
literals with datatype <tt>rdf:XMLLiteral</tt> can be represented
|
|
in a non-canonical
|
|
format, and canonicalization performed during the comparison between two
|
|
such literals. In this example the comparisons may be
|
|
being performed either between syntactic structures or
|
|
between their denotations in the domain of discourse.
|
|
Implementations that do not require any such comparisons can
|
|
hence be optimized.
|
|
</p>
|
|
</div>
|
|
|
|
<h3><a id="section-triples" name="section-triples">6.1 RDF
|
|
Triples</a><a id="xtocid103646" name="xtocid103646"> </a></h3>
|
|
|
|
<p>An <dfn><a id="dfn-rdf-triple" name="dfn-rdf-triple">RDF
|
|
triple</a></dfn> contains three components:</p>
|
|
|
|
<ul>
|
|
<li>the <dfn><a id="dfn-subject" name="dfn-subject">subject</a></dfn>,
|
|
which is an <a href="#dfn-URI-reference">RDF URI reference</a>
|
|
or a <a href="#dfn-blank-node">blank node</a>
|
|
</li>
|
|
|
|
<li>the <dfn><a id="dfn-predicate" name="dfn-predicate">predicate</a></dfn>, which is an <a href=
|
|
"#dfn-URI-reference">RDF URI reference</a></li>
|
|
|
|
<li>the <dfn><a id="dfn-object" name="dfn-object">object</a></dfn>,
|
|
which is an <a href="#dfn-URI-reference">RDF URI reference</a>,
|
|
a <a href="#dfn-literal">literal</a>
|
|
or a <a href="#dfn-blank-node">blank node</a>
|
|
</li>
|
|
|
|
</ul>
|
|
<p>An RDF triple is conventionally written in the order subject,
|
|
predicate, object.</p>
|
|
|
|
<p>The predicate is also known as the <dfn><a name="dfn-property"
|
|
id="dfn-property">property</a></dfn> of the triple.</p>
|
|
|
|
<h3><a id="section-rdf-graph" name="section-rdf-graph">6.2 RDF Graph</a><a id="xtocid103647" name="xtocid103647"> </a></h3>
|
|
|
|
<p>An <dfn><a id="dfn-rdf-graph" name="dfn-rdf-graph">RDF
|
|
graph</a></dfn> is a set of RDF triples.</p>
|
|
|
|
<p>The set of <dfn><a name="dfn-node" id="dfn-node">nodes</a><a name="section-Graph-Node" id="section-Graph-Node"> </a></dfn> of an RDF graph is the set of subjects and objects of
|
|
triples in the graph.</p>
|
|
|
|
|
|
<h3><a id="section-graph-equality" name="section-graph-equality">6.3 Graph
|
|
Equivalence</a></h3>
|
|
|
|
<p>Two RDF graphs <var>G</var> and <var>G'</var> are equivalent if there
|
|
is a bijection <var>M</var> between the nodes of the two graphs,
|
|
such that:</p>
|
|
|
|
<ol>
|
|
<li><var>M(lit)=lit</var> for all <a href=
|
|
"#dfn-literal">RDF literals</a> <var>lit</var> which
|
|
are nodes of either graph.</li>
|
|
|
|
<li><var>M(uri)=uri</var> for all <a href=
|
|
"#dfn-URI-reference">RDF URI references</a> <var>uri</var>
|
|
which are nodes of either graph.</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>With this definition, there are the same number of blank nodes in the two graphs,
|
|
and <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>.</p>
|
|
|
|
|
|
|
|
<h3><a id="section-Graph-URIref" name="section-Graph-URIref">6.4
|
|
RDF URI References</a></h3>
|
|
|
|
|
|
|
|
<p>A <dfn><a id="dfn-URI-reference" name="dfn-URI-reference">URI reference</a></dfn> within an RDF graph (an RDF URI reference) is a
|
|
Unicode string [<a href="#ref-unicode">UNICODE</a>] that
|
|
would produce a
|
|
valid URI character sequence (per RFC2396 [<a href=
|
|
"#ref-uris">URI</a>], sections 2.1)
|
|
representing an absolute URI with optional
|
|
fragment identifier
|
|
when subjected to the encoding described below.
|
|
</p>
|
|
<p>
|
|
The encoding consists of:
|
|
</p>
|
|
<ol>
|
|
<li>encoding the Unicode string as UTF-8
|
|
[<a href=
|
|
"#ref-rfc-2279">RFC-2279</a>], giving a sequence of octet values.
|
|
</li>
|
|
<li>
|
|
%-escaping octets that do not correspond to permitted US-ASCII characters.
|
|
</li>
|
|
</ol>
|
|
<p>
|
|
The disallowed octets that must be %-escaped include all those that do not
|
|
correspond to US-ASCII characters, and the excluded characters listed in
|
|
Section 2.4 of [<a href=
|
|
"#ref-uris">URI</a>], except for the number sign (#), percent sign (%),
|
|
and the square bracket characters re-allowed in [<a href=
|
|
"#ref-rfc-2732">RFC-2732</a>].
|
|
</p>
|
|
<p>
|
|
Disallowed octets must be escaped with the URI escaping mechanism (that is, converted to %HH,
|
|
where HH is the 2-digit hexadecimal numeral corresponding to the octet value).
|
|
</p>
|
|
|
|
|
|
<p>Two RDF URI references are equal if and only if they compare as
|
|
equal, character by character, as Unicode strings.</p>
|
|
|
|
<div class="note">
|
|
|
|
<p><strong>Note:</strong> RDF URI references are compatible with the <a
|
|
href=
|
|
"http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#anyURI"><cite>
|
|
anyURI</cite></a> datatype as defined by XML schema datatypes [<a
|
|
href="#ref-xml-schema2">XML-SCHEMA2</a>], constrained to be an
|
|
absolute rather than a relative URI reference.</p>
|
|
|
|
<p><strong>Note:</strong> RDF URI references are compatible with <a href=
|
|
"http://www.w3.org/TR/xml-names11/#IRIs">International Resource
|
|
Identifiers</a> as defined by [<a href="#ref-xml-names11">XML
|
|
Namespaces 1.1</a>].</p>
|
|
|
|
<p><strong>Note:</strong> The restriction to absolute URI references is
|
|
found in this abstract syntax. When there is a well-defined base
|
|
URI, concrete syntaxes, such as RDF/XML, may permit relative URIs
|
|
as a shorthand for such absolute URI references.</p>
|
|
</div>
|
|
|
|
<h3><a id="section-Graph-Literal" name="section-Graph-Literal">6.5
|
|
RDF Literals</a></h3>
|
|
|
|
|
|
<p>A <dfn><a id="dfn-literal" name="dfn-literal">literal</a></dfn> in an RDF graph
|
|
contains one or two named components.</p>
|
|
<p>All literals have a <dfn><a id="dfn-lexical-form" name=
|
|
"dfn-lexical-form">lexical form</a></dfn> being a Unicode [<a
|
|
href="#ref-unicode">UNICODE</a>] string in Normal Form C [<a
|
|
href="#ref-nfc">NFC</a>].</p>
|
|
|
|
|
|
<p><dfn><a id="dfn-plain-literal" name="dfn-plain-literal">Plain literals</a></dfn> have
|
|
a <a href="#dfn-lexical-form">lexical form</a> and optionally a
|
|
<dfn><a id="dfn-language-identifier" name=
|
|
"dfn-language-identifier">language tag</a></dfn> as
|
|
defined by [<a href="#ref-rfc-3066">RFC-3066</a>], normalized to lowercase.</p>
|
|
|
|
<p><dfn><a id="dfn-typed-literal" name="dfn-typed-literal">Typed literals</a></dfn> have a <a href="#dfn-lexical-form">lexical form</a> and a <dfn><a id="dfn-datatype-URI" name=
|
|
"dfn-datatype-URI">datatype URI</a></dfn> being an <a href=
|
|
"#dfn-URI-reference">RDF URI reference</a>.</p>
|
|
|
|
|
|
|
|
<div class="note">
|
|
<p><strong>Note:</strong> Literals in which the lexical form begins with a
|
|
composing character (as defined by [<a href=
|
|
"#ref-charmod">CHARMOD</a>]) are allowed however they may cause
|
|
interoperability problems, particularly with XML version 1.1 [<a
|
|
href="#ref-xml-1-1">XML 1.1</a>].</p>
|
|
|
|
<p><strong>Note:</strong> 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><strong>Note:</strong> 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>
|
|
|
|
</div>
|
|
|
|
<h4><a id="section-Literal-Equality" name=
|
|
"section-Literal-Equality">6.5.1 Literal Equality</a></h4>
|
|
|
|
<p>Two literals are equal if and only if all of the following
|
|
hold:</p>
|
|
|
|
<ul>
|
|
<li>The strings of the two lexical forms compare equal, character
|
|
by character.</li>
|
|
|
|
<li>Either both or neither have language tags.</li>
|
|
|
|
<li>The language tags, if any, compare
|
|
equal.</li>
|
|
|
|
<li>Either both or neither have datatype URIs.</li>
|
|
|
|
<li>The two datatype URIs, if any, compare equal, character by
|
|
character.</li>
|
|
</ul>
|
|
|
|
<p class="note"><strong>Note:</strong> RDF Literals are distinct and distinguishable
|
|
from RDF URI references; e.g. http://example.org as an RDF
|
|
Literal (untyped, without a language tag) is not equal to
|
|
http://example.org as an RDF URI reference.</p>
|
|
|
|
<h4><a id="section-Literal-Value" name=
|
|
"section-Literal-Value">6.5.2 The Value Corresponding to a Typed
|
|
Literal</a></h4>
|
|
|
|
<p>The datatype URI refers to a <a href=
|
|
"#section-Datatypes">datatype</a>. For XML Schema <a href=
|
|
"http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#built-in-datatypes">
|
|
built-in</a> datatypes, URIs such as
|
|
<span class="code">http://www.w3.org/2001/XMLSchema#int</span> are used. The URI
|
|
of the datatype <a href=
|
|
"#section-XMLLiteral" class="code">rdf:XMLLiteral</a> may be used.
|
|
There may be other, implementation dependent, mechanisms by which
|
|
URIs refer to datatypes.</p>
|
|
|
|
<p>The <em>value</em> associated with a typed literal is found by
|
|
applying the lexical-to-value mapping associated with the datatype URI to
|
|
the lexical form.
|
|
</p>
|
|
|
|
<p>
|
|
If the lexical form is not in
|
|
the lexical space of the datatype associated with the datatype URI,
|
|
then no literal value can be associated with the typed literal.
|
|
Such a case, while in error, is not <em>syntactically</em> ill-formed.</p>
|
|
<!--
|
|
<p>A typed literal for which the datatype does not map the lexical
|
|
form to a value is not syntactically ill-formed.</p>
|
|
-->
|
|
|
|
|
|
<p class="note"><strong>Note:</strong>
|
|
In application contexts, comparing the values of typed literals (see
|
|
<a href="#section-Literal-Value">
|
|
section
|
|
6.5.2</a>)
|
|
is usually more helpful than comparing their syntactic forms (see
|
|
<a href="#section-Literal-Equality">
|
|
section
|
|
6.5.1</a>).
|
|
Similarly, for comparing RDF Graphs,
|
|
semantic notions of entailment (see
|
|
[<a href=
|
|
"#ref-rdf-semantics">RDF-SEMANTICS</a>]) are usually
|
|
more helpful than syntactic equality (see
|
|
<a href="#section-graph-equality">
|
|
section
|
|
6.3</a>).</p>
|
|
<h3><a id="section-blank-nodes" name="section-blank-nodes">6.6 Blank Nodes</a></h3>
|
|
<p>
|
|
The <dfn><a id="dfn-blank-node" name="dfn-blank-node">blank nodes</a></dfn> in an RDF graph
|
|
are drawn from an infinite set.
|
|
This set of blank nodes, the set of all <a href="#dfn-URI-reference">RDF URI references</a>
|
|
and the set of all <a href="#dfn-literal">literals</a> are pairwise disjoint.
|
|
</p>
|
|
<p>
|
|
Otherwise, this set of blank nodes is arbitrary.
|
|
</p>
|
|
<p>RDF makes no reference to any internal structure of blank nodes.
|
|
Given two blank nodes, it is
|
|
possible to determine whether or not they are the same.</p>
|
|
|
|
|
|
<h2><a id="section-fragID" name="section-fragID">7. Fragment
|
|
Identifiers</a></h2>
|
|
|
|
<p>RDF uses an <a href="#dfn-URI-reference">RDF URI
|
|
Reference</a>, which may include a fragment identifier, as a
|
|
context free identifier for a resource. RFC 2396 [<a
|
|
href="#ref-uris">URI</a>] 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 a URI reference in an RDF graph is treated
|
|
with respect to the MIME type <span
|
|
class="code">application/rdf+xml</span> [<a
|
|
href="#ref-rdf-mime-type">RDF-MIME-TYPE</a>]. Given an RDF URI
|
|
reference consisting of an absolute URI and a fragment
|
|
identifier, the fragment identifer identifies the same thing
|
|
that it does in an <span
|
|
class="code">application/rdf+xml</span> representation of the
|
|
resource identified by the absolute URI component. Thus:</p>
|
|
<ul>
|
|
<li>we assume that the URI part (i.e. excluding fragment
|
|
identifier) identifies a resource, which is presumed to have
|
|
an RDF representation. So when <span
|
|
class="code">eg:someurl#frag</span> is used in an RDF
|
|
document, <span class="code">eg:someurl</span> is taken to
|
|
designate some RDF document (even when no such document can
|
|
be retrieved).</li>
|
|
<li><span class="code">eg:someurl#frag</span> means the thing
|
|
that is indicated, according to the rules of the <span
|
|
class="code">application/rdf+xml</span> MIME content-type as
|
|
a "fragment" or "view" of the RDF document at <span
|
|
class="code">eg:someurl</span>. If the document does not
|
|
exist, or cannot be retrieved, or is available only in
|
|
formats other than <span
|
|
class="code">application/rdf+xml</span>, 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 <span
|
|
class="code">application/rdf+xml</span> document acts as an
|
|
intermediary between some Web retrievable documents (itself,
|
|
at least, also any other Web retrievable URIs that it may
|
|
use, possibly including schema URIs 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 URI references 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 URIs
|
|
in an RDF graph.</p>
|
|
|
|
|
|
|
|
<h2 class="nonum"><a id="section-Acknowledgments" name=
|
|
"section-Acknowledgments">8. Acknowledgments</a></h2>
|
|
|
|
<p>This document contains a significant contribution from Pat
|
|
Hayes, Sergey Melnik and Patrick Stickler, under whose leadership
|
|
was developed the framework described in the RDF family of
|
|
specifications for representing datatyped values, such as integers
|
|
and dates.</p>
|
|
|
|
<p>The editors acknowledge valuable contributions from the
|
|
following: <!--</p>
|
|
|
|
<ul>-->
|
|
<!--<li>-->Frank Manola, <!--</li>-->
|
|
|
|
<!--<li>-->Pat Hayes, <!--</li>-->
|
|
|
|
<!--<li>-->Dan Brickley, <!--</li>-->
|
|
|
|
<!--<li>-->Jos de Roo, <!--</li>-->
|
|
|
|
<!--<li>-->Dave Beckett, <!--</li>-->
|
|
|
|
<!--<li>-->Patrick Stickler, <!--</li>-->
|
|
|
|
<!--<li>-->Peter F. Patel-Schneider, <!--</li>-->
|
|
|
|
<!--<li>-->Jerome Euzenat, <!--</li>-->
|
|
|
|
<!--<li>-->Massimo Marchiori, <!--</li>-->
|
|
|
|
<!--<li>-->Tim Berners-Lee, <!--</li>-->
|
|
|
|
<!--<li>-->Dave Reynolds <!--</li>-->
|
|
|
|
<!--<li>-->and Dan Connolly. <!--</li>-->
|
|
<!--
|
|
<li class="todo">[[[Other contributors]]]</li>
|
|
</ul>
|
|
-->
|
|
</p>
|
|
<p>Jeremy Carroll thanks <a href="mailto:oreste@w3.org">Oreste
|
|
Signore</a>, his host at the <a href="http://www.w3c.it/">W3C
|
|
Office in Italy</a> and <a href="http://www.isti.cnr.it" lang="it"
|
|
xml:lang="it">Istituto di Scienza e Tecnologie dell'Informazione
|
|
"Alessandro Faedo"</a>, part of the <a href="http://www.cnr.it"
|
|
lang="it" xml:lang="it">Consiglio Nazionale delle Ricerche</a>,
|
|
where Jeremy is a visiting researcher.</p>
|
|
|
|
<p>This document is a product of extended deliberations by the
|
|
RDFcore Working Group, whose members have included:
|
|
|
|
<!--</p><ul>-->
|
|
<!--<li>-->Art Barstow (W3C), <!--</li>-->
|
|
|
|
<!--<li>-->Dave Beckett (ILRT), <!--</li>-->
|
|
|
|
<!--<li>-->Dan Brickley (ILRT), <!--</li>-->
|
|
|
|
<!--<li>-->Dan Connolly (W3C), <!--</li>-->
|
|
|
|
<!--<li>-->Jeremy Carroll (Hewlett Packard), <!--</li>-->
|
|
|
|
<!--<li>-->Ron Daniel (Interwoven Inc), <!--</li>-->
|
|
|
|
<!--<li>-->Bill dehOra (InterX), <!--</li>-->
|
|
|
|
<!--<li>-->Jos De Roo (AGFA), <!--</li>-->
|
|
|
|
<!--<li>-->Jan Grant (ILRT), <!--</li>-->
|
|
|
|
<!--<li>-->Graham Klyne (Nine by Nine), <!--</li>-->
|
|
|
|
<!--<li>-->Frank Manola (MITRE Corporation), <!--</li>-->
|
|
|
|
<!--<li>-->Brian McBride (Hewlett Packard), <!--</li>-->
|
|
|
|
<!--<li>-->Eric Miller (W3C), <!--</li>-->
|
|
|
|
<!--<li>-->Stephen Petschulat (IBM), <!--</li>-->
|
|
|
|
<!--<li>-->Patrick Stickler (Nokia), <!--</li>-->
|
|
|
|
<!--<li>-->Aaron Swartz (HWG), <!--</li>-->
|
|
|
|
<!--<li>-->Mike Dean (BBN Technologies / Verizon), <!--</li>-->
|
|
|
|
<!--<li>-->R. V. Guha (Alpiri Inc), <!--</li>-->
|
|
|
|
<!--<li>-->Pat Hayes (IHMC), <!--</li>-->
|
|
|
|
<!--<li>-->Sergey Melnik (Stanford University) and <!--</li>-->
|
|
|
|
<!--<li>-->Martyn Horner (Profium Ltd). <!--</li>-->
|
|
</p> <!--</ul>-->
|
|
<p>This specification also draws upon an earlier RDF Model and
|
|
Syntax document edited by Ora Lassilla and Ralph Swick, and RDF
|
|
Schema edited by Dan Brickley and R. V. Guha. RDF and RDF Schema
|
|
Working Group members who contributed to this earlier work are:
|
|
|
|
<!--</p><ul>-->
|
|
<!--<li>-->Nick Arnett (Verity), <!--</li>-->
|
|
|
|
<!--<li>-->Tim Berners-Lee (W3C), <!--</li>-->
|
|
|
|
<!--<li>-->Tim Bray (Textuality), <!--</li>-->
|
|
|
|
<!--<li>-->Dan Brickley (ILRT / University of Bristol), <!--</li>-->
|
|
|
|
<!--<li>-->Walter Chang (Adobe), <!--</li>-->
|
|
|
|
<!--<li>-->Sailesh Chutani (Oracle), <!--</li>-->
|
|
|
|
<!--<li>-->Dan Connolly (W3C), <!--</li>-->
|
|
|
|
<!--<li>-->Ron Daniel (DATAFUSION), <!--</li>-->
|
|
|
|
<!--<li>-->Charles Frankston (Microsoft), <!--</li>-->
|
|
|
|
<!--<li>-->Patrick Gannon (CommerceNet), <!--</li>-->
|
|
|
|
<!--<li>-->R. V. Guha (Epinions, previously of Netscape
|
|
Communications), <!--</li>-->
|
|
|
|
<!--<li>-->Tom Hill (Apple Computer), <!--</li>-->
|
|
|
|
<!--<li>-->Arthur van Hoff (Marimba), <!--</li>-->
|
|
|
|
<!--<li>-->Renato Iannella (DSTC), <!--</li>-->
|
|
|
|
<!--<li>-->Sandeep Jain (Oracle), <!--</li>-->
|
|
|
|
<!--<li>-->Kevin Jones, (InterMind), <!--</li>-->
|
|
|
|
<!--<li>-->Emiko Kezuka (Digital Vision Laboratories), <!--</li>-->
|
|
|
|
<!--<li>-->Joe Lapp (webMethods Inc.), <!--</li>-->
|
|
|
|
<!--<li>-->Ora Lassila (Nokia Research Center), <!--</li>-->
|
|
|
|
<!--<li>-->Andrew Layman (Microsoft), <!--</li>-->
|
|
|
|
<!--<li>-->Ralph LeVan (OCLC), <!--</li>-->
|
|
|
|
<!--<li>-->John McCarthy (Lawrence Berkeley National Laboratory), <!--</li>-->
|
|
|
|
<!--<li>-->Chris McConnell (Microsoft), <!--</li>-->
|
|
|
|
<!--<li>-->Murray Maloney (Grif), <!--</li>-->
|
|
|
|
<!--<li>-->Michael Mealling (Network Solutions), <!--</li>-->
|
|
|
|
<!--<li>-->Norbert Mikula (DataChannel), <!--</li>-->
|
|
|
|
<!--<li>-->Eric Miller (OCLC), <!--</li>-->
|
|
|
|
<!--<li>-->Jim Miller (W3C, emeritus), <!--</li>-->
|
|
|
|
<!--<li>-->Frank Olken (Lawrence Berkeley National Laboratory), <!--</li>-->
|
|
|
|
<!--<li>-->Jean Paoli (Microsoft), <!--</li>-->
|
|
|
|
<!--<li>-->Sri Raghavan (Digital/Compaq), <!--</li>-->
|
|
|
|
<!--<li>-->Lisa Rein (webMethods Inc.), <!--</li>-->
|
|
|
|
<!--<li>-->Paul Resnick (University of Michigan), <!--</li>-->
|
|
|
|
<!--<li>-->Bill Roberts (KnowledgeCite), <!--</li>-->
|
|
|
|
<!--<li>-->Tsuyoshi Sakata (Digital Vision Laboratories), <!--</li>-->
|
|
|
|
<!--<li>-->Bob Schloss (IBM), <!--</li>-->
|
|
|
|
<!--<li>-->Leon Shklar (Pencom Web Works), <!--</li>-->
|
|
|
|
<!--<li>-->David Singer (IBM), <!--</li>-->
|
|
|
|
<!--<li>-->Wei (William) Song (SISU), <!--</li>-->
|
|
|
|
<!--<li>-->Neel Sundaresan (IBM), <!--</li>-->
|
|
|
|
<!--<li>-->Ralph Swick (W3C), <!--</li>-->
|
|
|
|
<!--<li>-->Naohiko Uramoto (IBM), <!--</li>-->
|
|
|
|
<!--<li>-->Charles Wicksteed (Reuters Ltd.), <!--</li>-->
|
|
|
|
<!--<li>-->Misha Wolf (Reuters Ltd.) and <!--</li>-->
|
|
|
|
<!--<li>-->Lauren Wood (SoftQuad). <!--</li>-->
|
|
<!--</ul>--></p>
|
|
|
|
<h2 class="nonum"><a id="section-References" name=
|
|
"section-References">9. References</a></h2>
|
|
|
|
<h3><a id="section-Normative-References" name=
|
|
"section-Normative-References"></a>9.1 Normative References</h3>
|
|
|
|
<dl>
|
|
<dt><a id="ref-rdf-syntax" name=
|
|
"ref-rdf-syntax"></a>[RDF-SYNTAX]</dt>
|
|
|
|
<dd><i><a href=
|
|
"http://www.w3.org/TR/2003/WD-rdf-syntax-grammar-20030905/">RDF/XML
|
|
Syntax Specification (Revised)</a></i>, Dave Beckett, World Wide
|
|
Web Consortium, 5 September 2003 (work in progress). This version
|
|
of the RDF/XML Syntax Specification (Revised) is
|
|
http://www.w3.org/TR/2003/WD-rdf-syntax-grammar-20030905/. The
|
|
latest version is at <a href=
|
|
"http://www.w3.org/TR/rdf-syntax-grammar/">http://www.w3.org/TR/rdf-syntax-grammar/</a>.</dd>
|
|
|
|
<dt><a id="ref-rdf-semantics" name=
|
|
"ref-rdf-semantics"></a>[RDF-SEMANTICS]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/2003/WD-rdf-mt-20030905/">RDF Semantics</a></cite>,
|
|
P. Hayes, World Wide
|
|
Web Consortium, 05 September 2003 (work in progress).
|
|
This version of the RDF Semantics is
|
|
http://www.w3.org/TR/2003/WD-rdf-mt-20030905/. The latest version
|
|
is at <a
|
|
href="http://www.w3.org/TR/rdf-mt/">http://www.w3.org/TR/rdf-mt/</a>.</dd>
|
|
|
|
|
|
<dt><a id="ref-rdf-mime-type" name=
|
|
"ref-rdf-mime-type"></a>[RDF-MIME-TYPE]</dt>
|
|
|
|
<dd><i><a href=
|
|
"http://www.ietf.org/internet-drafts/draft-swartz-rdfcore-rdfxml-mediatype-02.txt">
|
|
Application/rdf+xml Media Type Registration</a></i>, A. Swartz,
|
|
IETF Internet Draft, February 12 2003 (work in progress). Version
|
|
available at <a href=
|
|
"http://www.ietf.org/internet-drafts/draft-swartz-rdfcore-rdfxml-mediatype-02.txt">
|
|
http://www.ietf.org/internet-drafts/draft-swartz-rdfcore-rdfxml-mediatype-02.txt</a>.</dd>
|
|
|
|
<dt><a id="ref-xml" name="ref-xml"></a>[XML]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/2000/REC-xml-20001006">Extensible Markup
|
|
Language (XML) 1.0, Second Edition</a></cite>, T. Bray, J. Paoli,
|
|
C.M. Sperberg-McQueen and E. Maler, Editors. World Wide Web
|
|
Consortium. 6 October 2000. This version is
|
|
<span>http://www.w3.org/TR/2000/REC-xml-20001006</span>. The
|
|
latest version of XML is available at <a href=
|
|
"http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a>.</dd>
|
|
|
|
<dt><a id="ref-namespaces" name=
|
|
"ref-namespaces"></a>[XML-NS]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/1999/REC-xml-names-19990114/">Namespaces in
|
|
XML</a></cite>, T. Bray, D. Hollander and A. Layman, Editors.
|
|
World Wide Web Consortium. 14 January 1999. This version is
|
|
<span>http://www.w3.org/TR/1999/REC-xml-names-19990114/</span>.
|
|
The <a href="http://www.w3.org/TR/REC-xml-names/">latest version
|
|
of Namespaces in XML</a> is available at
|
|
http://www.w3.org/TR/REC-xml-names/.</dd>
|
|
|
|
<dt><a id="ref-rfc-2279" name="ref-rfc-2279"></a>[RFC-2279]</dt>
|
|
|
|
<dd><i><a href="http://www.isi.edu/in-notes/rfc2279.txt">RFC 2279
|
|
- UTF-8, a transformation format of ISO 10646</a></i>, F.
|
|
Yergeau, IETF, January 1998. This document is
|
|
http://www.isi.edu/in-notes/rfc2279.txt.</dd>
|
|
|
|
|
|
<dt><a id="ref-uris" name="ref-uris"></a>[URI]</dt>
|
|
|
|
<dd><cite><a href="http://www.isi.edu/in-notes/rfc2396.txt">RFC
|
|
2396 - Uniform Resource Identifiers (URI): Generic
|
|
Syntax</a></cite>, T. Berners-Lee, R. Fielding and L. Masinter,
|
|
IETF, August 1998. This document is
|
|
http://www.isi.edu/in-notes/rfc2396.txt.</dd>
|
|
<!--
|
|
<dt><a id="ref-http" name="ref-http"></a>[HTTP]</dt>
|
|
|
|
<dd><cite><a href="http://www.isi.edu/in-notes/rfc2616.txt">RFC
|
|
2616 - Hypertext Transfer Protocol - HTTP/1.1</a></cite>,
|
|
R. Fielding, UC Irvine, J. Gettys, J. Mogul, H. Frystyk, L. Masinter,
|
|
P. Leach,
|
|
T. Berners-Lee,
|
|
IETF, August 1998. This document is
|
|
http://www.isi.edu/in-notes/rfc2616.txt.</dd>
|
|
|
|
<dt><a id="ref-uri-reg" name="ref-uri-reg"></a>[URI-REG]</dt>
|
|
|
|
<dd><cite><a href="http://www.isi.edu/in-notes/rfc2717.txt">RFC
|
|
2717 - Registration Procedures for URL Scheme Names</a></cite>,
|
|
R. Petke and I. King, IETF, November 1999. This document is
|
|
http://www.isi.edu/in-notes/rfc2717.txt.</dd>
|
|
-->
|
|
<dt><a id="ref-rfc-2732" name="ref-rfc-2732"></a>[RFC-2732]</dt>
|
|
|
|
<dd><i><a href="http://www.isi.edu/in-notes/rfc2732.txt">RFC 2732
|
|
- Format for Literal IPv6 Addresses in URL's</a></i>, R. Hinden,
|
|
B. Carpenter and L. Masinter, IETF, December 1999. This document
|
|
is http://www.isi.edu/in-notes/rfc2732.txt.</dd>
|
|
|
|
|
|
<dt><a id="ref-unicode" name="ref-unicode"></a>[UNICODE]</dt>
|
|
|
|
<dd><cite>The Unicode Standard, Version 3</cite>, The Unicode
|
|
Consortium, Addison-Wesley, 2000. ISBN 0-201-61633-5, as updated
|
|
from time to time by the publication of new versions. (See <a
|
|
href=
|
|
"http://www.unicode.org/unicode/standard/versions/">http://www.unicode.org/unicode/standard/versions/</a>
|
|
for the latest version and additional information on versions of
|
|
the standard and of the Unicode Character Database).</dd>
|
|
|
|
<dt><a id="ref-nfc" name="ref-nfc"></a>[NFC]</dt>
|
|
|
|
<dd><a href=
|
|
"http://www.unicode.org/unicode/reports/tr15/"><cite>Unicode
|
|
Normalization Forms,</cite></a> Unicode Standard Annex #15, Mark
|
|
Davis, Martin Dürst. (See <a href=
|
|
"http://www.unicode.org/unicode/reports/tr15/">http://www.unicode.org/unicode/reports/tr15/</a>
|
|
for the latest version).</dd>
|
|
|
|
|
|
<dt><a id="ref-rfc-3066" name="ref-rfc-3066"></a>[RFC-3066]</dt>
|
|
|
|
<dd><i><a href="http://www.isi.edu/in-notes/rfc3066.txt">RFC 3066
|
|
- Tags for the Identification of Languages</a></i>, H.
|
|
Alvestrand, IETF, January 2001. This document is
|
|
http://www.isi.edu/in-notes/rfc3066.txt.</dd>
|
|
<!--
|
|
<dt><a id="ref-XML-C14N" name="ref-XML-C14N"></a>[XML-C14N]</dt>
|
|
|
|
<dd><a href=
|
|
"http://www.w3.org/TR/2001/REC-xml-c14n-20010315">Canonical
|
|
XML.</a> J. Boyer. W3C Recommendation, March 2001.</dd>
|
|
|
|
<dd>Available at <a href=
|
|
"http://www.w3.org/TR/2001/REC-xml-c14n-20010315">http://www.w3.org/TR/2001/REC-xml-c14n-20010315</a></dd>
|
|
|
|
<dd>Available at <a href=
|
|
"http://www.ietf.org/rfc/rfc3076.txt">http://www.ietf.org/rfc/rfc3076.txt</a></dd>
|
|
-->
|
|
<dt>
|
|
<a id="ref-xml-xc14n" name="ref-xml-xc14n">[XML-XC14N]</a>
|
|
</dt>
|
|
<dd><cite><a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/">Exclusive XML Canonicalization Version 1.0</a></cite>, J. Boyer, D.E. Eastlake 3rd, J. Reagle, Authors/Editors. W3C Recommendation. World Wide Web Consortium, 18 July 2002. This version of Exclusive XML Canonicalization is http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718. The <a href="http://www.w3.org/TR/xml-exc-c14n/">latest version of Canonical XML</a> is at http://www.w3.org/TR/xml-exc-c14n.
|
|
</dd>
|
|
|
|
<!--
|
|
<dt><a id="ref-keywords" name="ref-keywords"></a>[KEYWORDS]</dt>
|
|
|
|
<dd><cite><a href="http://www.ietf.org/rfc/rfc2119.txt">RFC 2119
|
|
- Key words for use in RFCs to Indicate Requirement
|
|
Levels</a></cite>, S. Bradner, IETF. March 1997. This document is
|
|
http://www.ietf.org/rfc/rfc2119.txt. </dd>
|
|
-->
|
|
<!--
|
|
<dt><a id="ref-rfc3023" name="ref-rfc3023"></a>[RFC-3023]</dt>
|
|
|
|
<dd><cite><a href="http://www.ietf.org/rfc/rfc3023.txt">RFC 3032
|
|
- XML Media Types</a></cite>, M. Murata, S. St.Laurent, D.Kohn,
|
|
IETF, January 2001. This document is
|
|
http://www.ietf.org/rfc/rfc3023.txt.</dd>
|
|
-->
|
|
<dt><a id="ref-xml-schema2" name=
|
|
"ref-xml-schema2"></a>[XML-SCHEMA2]</dt>
|
|
|
|
<dd><cite><a href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/">XML Schema
|
|
Part 2: Datatypes</a></cite>, W3C Recommendation, World Wide Web
|
|
Consortium, 2 May 2001.This version is
|
|
http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/. The <a href=
|
|
"http://www.w3.org/TR/xmlschema-2/">latest version</a> is available at
|
|
http://www.w3.org/TR/xmlschema-2/.</dd>
|
|
|
|
|
|
</dl>
|
|
|
|
<h3><a id="section-Informative-References" name=
|
|
"section-Informative-References"></a>9.2 Informational
|
|
References</h3>
|
|
<dl>
|
|
<dt><a id="ref-rdf-tests" name=
|
|
"ref-rdf-tests"></a>[RDF-TESTS]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/2003/WD-rdf-testcases-20030905/">RDF Test
|
|
Cases</a></cite>, Jan Grant and Dave Beckett, Editors. Work in
|
|
progress. World Wide Web Consortium, 5 September 2003. This version
|
|
of the RDF Test Cases is
|
|
<span>http://www.w3.org/TR/2003/WD-rdf-testcases-20030905/</span>.
|
|
The latest version of the RDF Test Cases is at <a href=
|
|
"http://www.w3.org/TR/rdf-testcases/">http://www.w3.org/TR/rdf-testcases/</a>.</dd>
|
|
|
|
|
|
<dt><a id="ref-rdf-primer" name=
|
|
"ref-rdf-primer"></a>[RDF-PRIMER]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/2003/WD-rdf-primer-20030905/">RDF
|
|
Primer</a></cite>, F. Manola, E. Miller, Editors, World Wide Web
|
|
Consortium W3C Working Draft, work in progress, 05 September 2003.
|
|
This version of the RDF Primer is
|
|
http://www.w3.org/TR/2003/WD-rdf-primer-20030905/. The <a href=
|
|
"http://www.w3.org/TR/rdf-primer/">latest version of the RDF
|
|
Primer</a> is at http://www.w3.org/TR/rdf-primer/.</dd>
|
|
|
|
<dt><a id="ref-rdf-vocabulary" name=
|
|
"ref-rdf-vocabulary"></a>[RDF-VOCABULARY]</dt>
|
|
|
|
<dd><i><a href="http://www.w3.org/TR/2003/WD-rdf-schema-20030905/">RDF Vocabulary
|
|
Description Language 1.0: RDF Schema</a></i>, Dan Brickley, R.V.
|
|
Guha, World Wide Web Consortium, 05 September 2003 (work in progress).
|
|
This version of the RDF Vocabulary
|
|
Description Language is http://www.w3.org/TR/2003/WD-rdf-schema-20030905/.
|
|
The latest version is at <a href=
|
|
"http://www.w3.org/TR/rdf-schema/">http://www.w3.org/TR/rdf-schema/</a>.</dd>
|
|
|
|
<dt><a id="ref-charmod" name="ref-charmod"></a>[CHARMOD]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/2002/WD-charmod-20020430/">Character Model
|
|
for the World Wide Web 1.0</a></cite>, M. Dürst, F. Yergeau,
|
|
R. Ishida, M. Wolf, A. Freytag, T Texin, Editors, World Wide Web
|
|
Consortium Working Draft, work in progress, 30 April 2002.
|
|
This version of the Character Model is
|
|
http://www.w3.org/TR/2002/WD-charmod-20020430/. The <a href=
|
|
"http://www.w3.org/TR/charmod/">latest version of the Character
|
|
Model</a> is at http://www.w3.org/TR/charmod/.</dd>
|
|
|
|
<dt><a id="ref-xml-1-1" name="ref-xml-1-1"></a>[XML-1.1]</dt>
|
|
|
|
<dd><cite><a href="http://www.w3.org/TR/2002/CR-xml11-20021015/">Extensible Markup
|
|
Language (XML) 1.1</a></cite>, John Cowan, Editor.
|
|
W3C Candidate Recommendation 15 October 2002.
|
|
This version is
|
|
http://www.w3.org/TR/2002/CR-xml11-20021015/. The <a href=
|
|
"http://www.w3.org/TR/xml11/">latest version</a> is available at
|
|
http://www.w3.org/TR/xml11/.</dd>
|
|
|
|
|
|
|
|
<dt><a id="ref-xml-schema1" name=
|
|
"ref-xml-schema1"></a>[XML-SCHEMA1]</dt>
|
|
|
|
<dd><cite><a href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/">XML Schema Part 1: Structures</a></cite>
|
|
W3C Recommendation, World Wide Web
|
|
Consortium, 2 May 2001.
|
|
This version is
|
|
http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/. The <a href=
|
|
"http://www.w3.org/TR/xmlschema-1/">latest version</a> is available at
|
|
http://www.w3.org/TR/xmlschema-1/.</dd>
|
|
|
|
<dt><a id="ref-xml-names11" name=
|
|
"ref-xml-names11"></a>[XML-NAMESPACES-1.1]</dt>
|
|
|
|
<dd><cite><a href="http://www.w3.org/TR/2002/CR-xml-names11-20021218/">Namespaces
|
|
in XML 1.1</a></cite>, Tim Bray, Dave Hollander, Andrew Layman,
|
|
Richard Tobin, Editors. W3C Candidate Recommendation 18 December 2002.
|
|
This version is
|
|
http://www.w3.org/TR/2002/CR-xml-names11-20021218/. The <a href=
|
|
"http://www.w3.org/TR/xml-names11/">latest version</a> is available at
|
|
http://www.w3.org/TR/xml-names11/.</dd>
|
|
|
|
<dt><a id="ref-xml-infoset" name=
|
|
"ref-xml-infoset"></a>[XML-INFOSET]</dt>
|
|
|
|
<dd><i><a href="http://www.w3.org/TR/2001/REC-xml-infoset-20011024/">XML
|
|
Information Set</a></i>, John Cowan and Richard Tobin, W3C
|
|
Recommendation, 24 October 2001. This document is
|
|
http://www.w3.org/TR/2001/REC-xml-infoset-20011024/.
|
|
The <a href=
|
|
"http://www.w3.org/TR/xml-infoset/">latest version</a> is available at
|
|
http://www.w3.org/TR/xml-infoset/.</dd>
|
|
|
|
<dt>
|
|
<a id="ref-xpath" name="ref-xpath">[XPATH]</a>
|
|
</dt>
|
|
<dd><cite><a href="http://www.w3.org/TR/1999/REC-xpath-19991116">XML Path Language (XPath) Version 1.0</a></cite>, J. Clark and S. DeRose, Editors. World Wide Web Consortium, 16 November 1999. This version of XPath is <span>http://www.w3.org/TR/1999/REC-xpath-19991116</span>. The <a href="http://www.w3.org/TR/xpath">latest version of XPath</a> is at <span>http://www.w3.org/TR/xpath</span>.
|
|
</dd>
|
|
<!--
|
|
<dt><a id="ref-xmlschema0" name=
|
|
"ref-xmlschema0"></a>[XML-SCHEMA0]</dt>
|
|
|
|
<dd><cite><a href="http://www.w3.org/TR/xmlschema-0/">XML Schema
|
|
Part 0: Primer - W3C Recommendation</a></cite>, World Wide Web
|
|
Consortium, 2 May 2001.</dd>
|
|
|
|
<dt><a id="ref-xmlschema1" name=
|
|
"ref-xmlschema1"></a>[XML-SCHEMA1]</dt>
|
|
|
|
<dd><cite><a href="http://www.w3.org/TR/xmlschema-1/">XML Schema
|
|
Part 1: Structures - W3C Recommendation</a></cite>, World Wide
|
|
Web Consortium, 2 May 2001.</dd>
|
|
-->
|
|
|
|
<dt><a id="ref-owl" name="ref-owl"></a>[OWL]</dt>
|
|
|
|
<dd><a href=
|
|
"http://www.w3.org/TR/2003/CR-owl-ref-20030818/"><i>OWL Web
|
|
Ontology Language Reference</i></a>, Mike Dean, Guus Schreiber.
|
|
W3C
|
|
Candidate Recommendation 18 August 2003.
|
|
Latest version is available at <a
|
|
href=
|
|
"http://www.w3.org/TR/owl-ref/">http://www.w3.org/TR/owl-ref/</a>.</dd>
|
|
|
|
<!--
|
|
<dt><a id="ref-sowa" name="ref-sowa"></a>[SOWA]</dt>
|
|
|
|
<dd><i>Knowledge Representation: Logical, Philosophical and
|
|
Computational Foundations</i>, John F. Sowa, Brookes/Cole, 2000.
|
|
ISBN 0-534-94965-7.</dd>
|
|
|
|
<dt><a id="ref-notation3" name=
|
|
"ref-notation3"></a>[NOTATION3]</dt>
|
|
|
|
<dd>Tim Berners-Lee, DesignIssues note on N3, ...</dd>
|
|
-->
|
|
<dt><a id="ref-rdf-ms" name="ref-rdf-ms"></a>[RDF-MS]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/">Resource
|
|
Description Framework (RDF) Model and Syntax
|
|
Specification</a></cite>, O. Lassila and R. Swick, Editors. World
|
|
Wide Web Consortium. 22 February 1999. This version is
|
|
http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/. The <a href=
|
|
"http://www.w3.org/TR/REC-rdf-syntax/">latest version of RDF
|
|
M&S</a> is available at
|
|
http://www.w3.org/TR/REC-rdf-syntax/.</dd>
|
|
<dt><a id="ref-xhtml" name="ref-xhtml"></a>[XHTML]</dt>
|
|
|
|
<dd><cite><a href=
|
|
"http://www.w3.org/TR/2002/REC-xhtml1-20020801/">XHTML
|
|
1.0 The Extensible HyperText Markup Language (Second Edition)</a></cite>,
|
|
|
|
World
|
|
Wide Web Consortium. 26 January 2000, revised 1 August 2002. This version is
|
|
http://www.w3.org/TR/2002/REC-xhtml1-20020801/. The <a href=
|
|
"http://www.w3.org/TR/xhtml1/">latest version of XHTML 1</a> is available at
|
|
http://www.w3.org/TR/xhtml1/.</dd>
|
|
<!--
|
|
<dt><a id="ref-rdf-schema" name=
|
|
"ref-rdf-schema"></a>[RDF-SCHEMA]</dt>
|
|
|
|
<dd><i><a href="http://www.w3.org/TR/2000/CR-rdf-schema-20000327/">
|
|
Resource
|
|
Description Framework (RDF) Schema Specification 1.0</a></i>, Dan
|
|
Brickley and R. V. Guha, W3C Candidate Recommendation, 27 March
|
|
2000. This document is http://www.w3.org/TR/2000/CR-rdf-schema-20000327/.</dd>
|
|
-->
|
|
</dl>
|
|
<h1><a id="section-Revisions" name="section-Revisions">Appendix
|
|
A: Revisions since</a>
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/">last-call draft 23 January 2003</a></h1>
|
|
<p>We divide these into non-editorial and editorial.
|
|
The non-editorial changes also list consquential editorials changes.
|
|
Editorial changes are those which do not result in any change in
|
|
the meaning of an RDF document or the behaviour of an RDF application.</p>
|
|
<h2><a id="section-substantive-Revisions" name="section-substantive-Revisions">Appendix
|
|
A.1: Non-Editorial Revisions</a></h2>
|
|
<dl>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-14">
|
|
pfps-14</a></dt>
|
|
<dd>Deleted
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-Meaning">
|
|
section 4 about social meaning</a>.
|
|
cf
|
|
<a href="http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0486.html">msg from meeting at tech plenary</a>.
|
|
|
|
Also removed
|
|
previous
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-agreements">section 2.2.8</a> ("A Basis for Binding Agreements") as
|
|
this also related to social meaning. Also: removed mention in
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-Datatypes">section
|
|
3.3. Datatypes</a> about the defining authority of a datatype URI. Small
|
|
consequential changes in abstract and introduction and
|
|
<a href="#section-design-goals">bulleted list at start of section 2.2</a>.
|
|
Consequential deletion of
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#ref-http">[HTTP]</a>
|
|
and
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#ref-uri-reg">[URI-REG]</a>
|
|
references.</dd>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#macgregor-01">
|
|
macgregor-01</a>, <a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#macgregor-02">
|
|
macgregor-02</a></dt>
|
|
<dd>These issues, about distinguishing asserted and
|
|
non-asserted statements and propositional attitudes, aref
|
|
addressed by the removal of
|
|
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-Meaning">section 4</a>,
|
|
which raised doubts
|
|
about their inclusion in RDF.</dd>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#danc-02">
|
|
danc-02 goofy literals</a></dt>
|
|
<dd>The
|
|
<a href="#section-Graph-Literal">definition of literal</a> was reworked to exclude the case
|
|
of a typed literal with a language tag. Also changed from using the term
|
|
language identifier to use the term langauge tag.
|
|
(<a href="#section-Literals"> Section 3.4</a> also affected).
|
|
See also
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0138.html">WG resolution on typed literals</a>.
|
|
</dd>
|
|
<!--
|
|
<dt>Whitespace in XSD typed literals
|
|
(<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-02">
|
|
xmlsch-02</a>)</dt>
|
|
<dd>It is clarified that the whiteSpace facet formally has no effect,
|
|
but in line with
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Aug/0215.html">
|
|
WG resolution</a> a normative note is added, permitting
|
|
implementations to nevertheless perform whiteSpace normalization.
|
|
The introduction is modified to permit normative notes, a new reference
|
|
to RFC 2119 is added, for the keywords.
|
|
</dd>
|
|
-->
|
|
<dt>XMLLiteral simplification</dt>
|
|
<dd>There has been a significant simplication in <a href="#section-XMLLiteral">this part</a> of the document.
|
|
<dl>
|
|
<dt>
|
|
<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#reagle-01">
|
|
reagle-01</a>,
|
|
<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#reagle-02">
|
|
reagle-02</a>
|
|
</dt>
|
|
<dd>
|
|
Exclusive canonicalization is now used throughout, and the lexical-to-value
|
|
mapping has been simplified, with the real work being done in the RDF syntax document.
|
|
Added a new implementation note at very end of section 6 to indicate that
|
|
canonicalization is not needed for some RDF applications.
|
|
</dd>
|
|
|
|
<dt>language tag</dt>
|
|
<dd>As per <a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0138.html">WG resolution</a>
|
|
this is no longer significant.
|
|
Consequential changes in <a href="#section-Literal-Value">section 6.5.2</a>
|
|
</dd>
|
|
<dt>
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0224.html">
|
|
I18N clarification</a></dt>
|
|
<dd>As per
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0236.html">
|
|
WG decision</a>,
|
|
a paragraph is added to <a href="#section-Literals">section 3.4</a> to encourage use of XML Literal
|
|
when markup may be required. Added informative reference to <a href="#ref-xhtml">[XHTML]</a>.
|
|
</dd>
|
|
<dt>
|
|
<a href="http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0434.html">Wrapping</a></dt>
|
|
<dd>This is dropped, as in the <a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0138.html">WG resolution</a>.
|
|
</dd>
|
|
<dt>value space</dt>
|
|
<dd>The current text was approved by WG decision on
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Aug/0215">15th August</a>.
|
|
</dd>
|
|
<dt>references</dt>
|
|
<dd>The old reference to
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#ref-XML-C14N">C14N</a>
|
|
is replaced by one to <a href="#ref-xml-xc14n">EXC-C14N</a>.</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><a href=
|
|
"http://www.w3.org/2001/sw/RDFCore/20030123-issues/#williams-02">williams-02</a></dt>
|
|
<dd>Given changes in advice from I18N, we deleted the normalization form C
|
|
constraint from <a href="#dfn-URI-reference">RDF URI references definition</a>.</dd>
|
|
<dt>
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0164">
|
|
Removed nomormative dependency on RDFS</a></dt>
|
|
<dd>As per
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0236">
|
|
WG decision</a>, <a href="#section-URIspaces">section 4</a> has had
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-URIspaces">
|
|
old text to do with the
|
|
RDFS namespace</a> deleted. Consequential editorial changes.
|
|
<a href="#ref-rdf-vocabulary" >[RDF-VOCABULARY]</a>
|
|
changed to being an informative reference.
|
|
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#ref-rdf-schema">Reference to old version of schema</a> dropped.
|
|
</dd>
|
|
<dt>
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0330">
|
|
absolute URIs</a></dt>
|
|
<dd>
|
|
The <em>normative</em> restriction to absolute URIs had got lost
|
|
in the LC working draft due to editorial error. This restriction
|
|
was still stated in informative text. The phrase "representing an absolute URI with optional
|
|
fragment identifier" is added
|
|
to <a href="#section-Graph-URIref">section 6.4</a>.
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
<h2><a id="section-editorial-Revisions" name="section-editorial-Revisions">Appendix
|
|
A.2: Editorial Revisions</a></h2>
|
|
<dl>
|
|
<dt>Clarifying datatypes</dt>
|
|
<dd>The normative text concerning datatypes is reworked.
|
|
The old text from <a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-Datatypes">section 3.3</a>
|
|
is replaced by updated text in <a href="#section-Datatypes">section 5</a>.
|
|
Specific changes concern:
|
|
<dl> <dt>
|
|
<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-02">
|
|
xmlsch-02</a></dt>
|
|
<dd>Concerning the whiteSpace facet is also addressed by that same note, just before section 5.1.
|
|
</dd>
|
|
<dt>
|
|
<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-03">
|
|
xmlsch-03</a></dt>
|
|
<dd>we globally use the term lexical-to-value mapping instead of
|
|
datatype mapping or any other term</dd>
|
|
<dt>
|
|
<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-04">
|
|
xmlsch-04</a></dt>
|
|
<dd>We do not change the definition of value space but add a note, just before section 5.1,
|
|
clarifying the relationship with XML Schema datatypes.
|
|
</dd>
|
|
<dt>
|
|
<a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-13">
|
|
pfps-13</a></dt>
|
|
<dd>Concerning facets is addressed by that same note, just before section 5.1.
|
|
</dd>
|
|
<dt>inappropriate XML schema datatypes</dt>
|
|
<dd>A link to the new discussion in RDF Semantics is provided.</dd>
|
|
</dl>
|
|
</dd>
|
|
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#tex-01">
|
|
tex-01</a></dt>
|
|
<dd>Add new note at end of
|
|
<a href="#section-Graph-Literal">section 6.5</a> concerning case of language tags</dd>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#williams-01">
|
|
williams-01</a></dt>
|
|
<dd>Reworked text in section 3.2 to be more consistent with
|
|
view of URIs as nodes (rather than node labels). Included
|
|
revised introduction of node concept in section 3.1. Used
|
|
some of <a
|
|
href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Feb/0152.html">
|
|
Pat Hayes' suggested text</a> in section 3.1. Also some
|
|
impact on rewording in section 2.2.6. Some further small
|
|
reworking of sections 3.1, 3.2 in response to RDFcore mailing
|
|
list comments. Added last sentence to <a href="#section-blank-nodes">section 6.6</a>.
|
|
</dd>
|
|
<dd>Changed arc to predicate in <a href="#section-Literals">section 3.4</a></dd>
|
|
<dt><a href=
|
|
"http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0370.html">predicate
|
|
or property</a></dt>
|
|
<dd>Section 3.1, replace use of "property" by "predicate", also in
|
|
<a href="Graph-ex.gif">picture</a>.
|
|
Similarly, other uses throughout the document. The term
|
|
"property" still appears, but "predicate" is now used as the
|
|
lead term. The naming convention is that
|
|
predicate, node, triple are
|
|
preferred as syntactic terms; property, resource, statement are preferred
|
|
as semantic terms.</dd>
|
|
<dt>Related to
|
|
<a href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-15">pfps-15 on the Primer</a></dt>
|
|
<dd>Deleted section
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-expression-simple">2.2.7</a> (which didn't say anything not
|
|
already covered by section 2.2.6), and
|
|
revised title and wording
|
|
of <a href="#section-anyone">section 2.2.6</a>. </dd>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-22">
|
|
pfps-22</a>, <a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-22">
|
|
pfps-23</a></dt>
|
|
<dd>Revised text in section 4 to clarify role of RDF(S)
|
|
vocabulary. Also changed term "URI" to "URI reference".</dd>
|
|
<dd>After
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0006">further discussion</a>
|
|
with the commentator,
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0173">
|
|
further changes</a>
|
|
were agreed by the WG.</dd>
|
|
<dt>FragID clarifications</dt>
|
|
<dd>Reworked text in <a href="#section-fragID">section 7</a> to clarify
|
|
its intent, and
|
|
added note that retrieval of resource representation is not
|
|
required . This in response to last-call comments from
|
|
<a href="http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0238.html">Stuart
|
|
Williams</a> and
|
|
<a href="http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0363.html">Massimo Marchiori</a>.</dd>
|
|
<dt>
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0175">
|
|
Removed term RDF Core</a></dt>
|
|
<dd>As per
|
|
<a href="http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0236">
|
|
WG decision</a>, the term RDF Core has been replaced throughout.
|
|
In particular title of <a href="#section-URIspaces">section 4</a> changed.
|
|
Minor changes to <a href="#section-Introduction">section 1</a>, and the body
|
|
of <a href="#section-URIspaces">section 4</a>.
|
|
</dd>
|
|
|
|
<dt >language identifier vs language tag</dt>
|
|
<dd >globally replaced "langauge identifier" with "language tag"</dd>
|
|
<dt>Namespace name</dt>
|
|
<dd>
|
|
Also changed "namespace URI" to
|
|
"namespace name", to be more consistent with XML namespace
|
|
termonology.</dd>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-18">
|
|
pfps-18</a></dt>
|
|
<dd>While this comment was accepted, it has not resulted in any changes in this documented.</dd>
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#danc-01">
|
|
danc-01</a></dt>
|
|
<dd>s/equal/equivalent/ in <a href="#section-graph-equality">section 6.3</a></dd>
|
|
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#xmlsch-06">
|
|
xmlsch-06 natural language data
|
|
</a></dt>
|
|
<dd>
|
|
s/should/may/ in
|
|
<a href="#section-Literals">section 3.4</a>.</dd>
|
|
|
|
<dt><a
|
|
href="http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-16">
|
|
pfps-16</a></dt>
|
|
<dd>
|
|
Removed one false sentence from section 3.5 concerning expressive power; and consequentially
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#ref-sowa">[SOWA] reference</a>.</dd>
|
|
|
|
<dt >deleted editors note concerning tag issue IRI-Everywhere</dt>
|
|
|
|
<dt>Renumbering</dt>
|
|
<dd>Renumbered previous
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-URIspaces">section 3.7</a>
|
|
to
|
|
<a href="#section-URIspaces">section 4</a>, as it doesn't
|
|
really seem to belong in "Concepts" (and to minimize
|
|
renumbering of the document). </dd>
|
|
<dd >Renumbered old
|
|
<a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-XMLLiteral">
|
|
section 5</a> as <a href="#section-XMLLiteral">5.1</a>, and moved the normative text of
|
|
old <a href="http://www.w3.org/TR/2003/WD-rdf-concepts-20030123/#section-Datatypes">section 3.3</a>
|
|
to become the new <a href="#section-Datatypes">section 5</a>, leaving the
|
|
new <a href="#section-Datatypes-intro">section 3.3</a> as informative.</dd>
|
|
<dd >Permitted additionally clarification in
|
|
<a href="#section-Introduction">bulleted list in introduction</a>
|
|
as to which parts of this documents are normative.</dd>
|
|
<dd >Consequential changes to <a href="#section-Structure">section 1.1</a>.</dd>
|
|
|
|
|
|
<dt><a href="http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0489">Typos from XMLSCH-WG</a></dt>
|
|
<dd >
|
|
s/syntacticly/syntactically/ in <a href="#section-Literal-Value">section 6.5.2</a>.
|
|
</dd>
|
|
<dd >s/element tag/element/ in <a href="#section-XMLLiteral">section 5.1</a>,
|
|
note the text has changed so that the exact instance of the problem did not occur, but the
|
|
term, as corrected still does.</dd>
|
|
<dd >s/XML element content/XML data/ in <a href="#section-XMLLiteral">section 5.1</a>.</dd>
|
|
|
|
<dt>Polishing</dt>
|
|
<dd>Deleted most of some spurious repetitive discursive text in
|
|
<a href="#section-Structure">
|
|
section 1.1</a>, moved contentful phrase into <a href="#section-Introduction">section 1.</a></dd>
|
|
<dd>Minor changes in <a href="#section-design-goals">bulleted list at start of section 2.2</a></dd>
|
|
<dd>Minor fix to reference in note of <a href="#section-simple-data-model">section 2.2.1</a></dd>
|
|
<dd>Two word simplification in bullet list at start of <a href="#section-Concepts">section 3</a></dd>
|
|
<dd>s/Representation/RDF Expression/ in title of <a href="#section-SimpleFacts">section 3.5</a></dd>
|
|
|
|
<dd >s/and/combined with/ in second bullet in <a href="#section-Literals">section 3.4</a></dd>
|
|
<dd >added "set of" to definition of <a href="#dfn-node">nodes</a></dd>
|
|
<dd >Replaced "The language tags of the two lexical forms compare equal." with
|
|
"The language tags, if any, compare equal. " in <a href="#section-Literal-Equality">section 6.5.1</a>.</dd>
|
|
|
|
<dd >Added "of blank nodes" to
|
|
<a href="#section-blank-nodes">section 6.6</a></dd>
|
|
<dd >Updated figure and changed ZIP to POSTALCODE in 3.5 to track changes in the primer.</dd>
|
|
<dd >
|
|
Deleted duplicate sentence at end of in <a href="#section-Literal-Value">section 6.5.2</a>.
|
|
</dd>
|
|
<dd >Added "mentioned" to
|
|
<a href="#section-Introduction">section 1</a>.</dd>
|
|
<dd >removed italics from lingua franca
|
|
<a href="#section-motivation">
|
|
2.1</a></dd>
|
|
<dd>s/which/that/ in <a href="#section-Literals">section 3.4</a></dd>
|
|
<dd>s/objects/things/ in <a href="#section-SimpleFacts">section 3.5</a></dd>
|
|
<dd>s/relates only/only relates/ in <a href="#section-Graph-Literal">section 6.5</a></dd>
|
|
<dt >References</dt>
|
|
<dd >Updated links to <a href="#ref-owl">[OWL]</a>,
|
|
<a href= "#ref-xml-names11">[XML-NAMESPACES-1.1]</a>,
|
|
<a href="#ref-xml-1-1">[XML-1.1]</a>,
|
|
<a href="#ref-charmod">[CHARMOD]</a>,
|
|
<a href="#ref-rdf-mime-type"> [RDF-MIME-TYPE]</a>.
|
|
Used dated URIs where possible:
|
|
change to <a href= "#ref-xml-names11">[XML-NAMESPACES-1.1]</a>,
|
|
<a href="#ref-xml-1-1">[XML-1.1]</a>,
|
|
<a href= "#ref-xml-schema2">[XML-SCHEMA2]</a>,
|
|
<a href="#ref-xml-infoset">[XML-INFOSET]</a>.
|
|
New reference to <a href="#ref-xml-schema1">XML Schema part 1</a>.
|
|
</dd>
|
|
|
|
</dl>
|
|
|
|
|
|
<hr />
|
|
<div class="metadata">
|
|
<p><a href="metadata.rdf"><img
|
|
src="rdf_meta.gif" alt="RDF/XML Metadata" /></a></p>
|
|
|
|
</div>
|
|
</body>
|
|
</html>
|
|
|