March 5. Section on datatypes revized to conform better to Concepts, hopefully also with PFPS' concerns.
authorPat Hayes <phayes@ihmc.us>
Tue, 05 Mar 2013 21:15:10 -0600
changeset 622 5de7a3a4b6d3
parent 616 e57ebaf12a77
child 623 5b5aaa377c84
March 5. Section on datatypes revized to conform better to Concepts, hopefully also with PFPS' concerns.
rdf-mt/index.html
--- a/rdf-mt/index.html	Fri Mar 01 15:14:19 2013 -0600
+++ b/rdf-mt/index.html	Tue Mar 05 21:15:10 2013 -0600
@@ -539,7 +539,7 @@
 
   <body style="display: inherit; "><div class="head"><p><a href="http://www.w3.org/"></a></p>
 <h1 property="dcterms:title" class="title" id="title">RDF 1.1 Semantics</h1>
-<h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-03-01T00:00:00+0000" id="w3c-working-draft-1-March-2013"> Editors Working Draft 1 March 2013</h2><dl><dt>This version:</dt><dd><a href="https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html">https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html</a></dd><dt>Latest published version:</dt><dd><a href=""></a></dd><dt>Latest editor's draft:</dt><dd><a href=""></a></dd>
+<h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-03-05T00:00:00+0000" id="w3c-working-draft-5-March-2013"> Editors Working Draft 5 March 2013</h2><dl><dt>This version:</dt><dd><a href="https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html">https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html</a></dd><dt>Latest published version:</dt><dd><a href=""></a></dd><dt>Latest editor's draft:</dt><dd><a href=""></a></dd>
 <dt>Previous version:</dt><dd><a rel="dcterms:replaces" href=""></a></dd><dt>Latest recommendation:</dt><dd><a href="http://www.w3.org/TR/rdf-mt/">http://www.w3.org/TR/rdf-mt/</a></dd><dt>Editors:</dt><dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Patrick Hayes" href="http://www.ihmc.us/groups/phayes/">Patrick Hayes</a>, <a rel="foaf:workplaceHomepage" href="http://www.ihmc.us/index.php">Florida IHMC</a></span>
 </dd>
 <dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Peter F. Patel-Schneider" href="////">Peter F. Patel-Schneider</a>, <a rel="foaf:workplaceHomepage" href="////">////</a></span>
@@ -826,24 +826,21 @@
 
 <p class="changenote">  In the 2004 RDF 1.0 specification, datatype D-entailment was defined as a semantic extension of RDFS-entailment. Here it is defined as a direct extension to basic RDF. This is more in conformity with actual usage, where RDF with datatypes is widely used without the RDFS vocabulary. If there is a need to distinguish this from the 2004 RDF 1.0 terminology, the longer phrasing "simple D-entailment" or "simple datatype entailment" should be used rather than "D-entailment". </p>
 
-<p>RDF literals are either language-tagged literals or datatyped literals which 
-combine a string and an IRI identifying a datatype. A datatype is understood to define a partial mapping from character strings to values, and the literal then refers to the value obtained by applying the datatype mapping to the character string. If this mapping gives no value for the literal string, then the literal also has no value. </p>
-
-<p>RDF literal syntax allows any IRI to be used in a typed literal, even when it does not identify a datatype. Interpretations will vary according to how many IRIs they recognize as denoting datatypes, so we will refer to a set D of <em>recognized datatype IRIs</em> and treat this as a parameter on interpretations, and hence upon entailments. Literals with an "unknown" datatype, that is, with a datatype IRI which is not in the set of recognized datatypes, are treated like IRI names and assumed to denote some thing in the universe IR. </p>
 
-<p class="changenote">  In the 2004 RDF 1.0 specification, D was defined as a datatype mapping from IRIs to datatypes, rather than simply as a set of IRIs. </p>
-
+<p>RDF literals and datatypes are fully described in ///Concepts///. In summary: RDF literals are either language-tagged strings, or datatyped literals which 
+combine a string and an IRI identifying a datatype. A datatype is understood to define a partial mapping, the <em>lexical-to-value mapping</em>, from character strings to values, and the literal refers to the value obtained by applying the datatype mapping to the character string. If this mapping gives no value for the literal string, then the literal has no referent.  A literal whose datatype IRI is recognized, but whose character string is not in the domain of the datatype lexical-to-value mapping, is called <em>ill-typed</em>. A literal which is not ill-typed is <em>well-typed</em>. The <em> value space</em> of a datatype is the range of the lexical-to-value mapping, i.e. the set of all values of well-typed literals of that datatype.
+Datatypes are indicated by IRIs, formally in terms of a <em>datatype map</em> from a set of <em>recognized</em> IRIs to datatypes.
+</p>
 
-<p>The semantics of datatypes assumes that datatype IRIs denote things called datatypes in the universe, and that every recognized datatype d has a corresponding lexical-to-value mapping L2V(d) from character strings to semantic values. For example,</p><p> L2V(<code>http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#decimal</code>)('24') </p><p> is the number twenty-four. Lexical-to-value mappings are defined by the specification of the datatype, externally to RDF. </p>
+<p> Interpretations will vary according to which IRIs they recognize as denoting datatypes. We describe this using a parameter D on interpretations. where D is a datatype map. We will indicate a datatype map by the set of recognized datatype IRIs. </p>
 
-<p> A literal whose datatype IRI is recognized, but whose character string is not in the domain of the datatype lexical-to-value mapping, is called <em>ill-typed</em>. A literal which is not ill-typed is <em>well-typed</em>. The <em> value space</em> of a datatype is the range of the lexical-to-value mapping, i.e. the set of all values of well-typed literals of that datatype. </p>
+<p>RDF literal syntax allows any IRI to be used in a typed literal, even when it does not identify a datatype. Literals with an "unknown" datatype IRI which is not in the set of recognized datatypes, are treated like IRI names and assumed to denote some thing in the universe IR. </p>
 
 <p>Language-tagged strings are an exceptional case which are given a special treatment. The IRI <code>rdf:langString</code> is classified as a datatype IRI, and interpreted to refer to a datatype, even though no L2V mapping is defined for it. The value space of <code>rdf:langString</code> is the set of all pairs of a string with a language tag. The semantics of literals with this as their type are given below. (If datatype L2V mappings were defined on pairs of lexical values rather than strings, then the L2V mapping for <code>rdf:langString</code> would be the identity function on pairs of the form < unicode string, language tag >. But as they are not, we simply list this as a special case.)</p>
 
 <p class="issue">This will require alignment with Concepts.  rdf:langString may have an L2V mapping which is ignored by the semantics. Concepts currently states that it is not a datatype even though the IRI is a datatype IRI. </p>
 
-
-<p>D-interpretations <strong class="RFC2119">MUST</strong> interpret any IRI listed in <a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/#xsd-datatypes">///Concepts Section 5///</a> as described there, and the IRI <code>rdf:plainLiteral</code> <strong class="RFC2119">MUST</strong> be interpreted to refer to the datatype defined in <a href="www.w3.org/TR/rdf-plain-literal/">///PlainLiteral///</a>. </p>
+<p>Datatype maps <strong class="RFC2119">MUST</strong> interpret any IRI listed in <a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/#xsd-datatypes">///Concepts Section 5///</a> as described there, and the IRI <code>rdf:plainLiteral</code> <strong class="RFC2119">MUST</strong> be interpreted to refer to the datatype defined in <a href="www.w3.org/TR/rdf-plain-literal/">///PlainLiteral///</a>. When other datatypes are used, the mapping between a recognized IRI and the datatype it refers to <strong class="RFC2119">MUST</strong> be specified unambiguously, and be fixed during all RDF transformations or manipulations.</p>
 
 
 <h3>D-interpretations</h3>
@@ -999,7 +996,7 @@
 <p><a id="rdfsinterpdef" name="rdfsinterpdef"></a> An <i>rdfs-D-interpretation</i>  is an <a href="#rdfinterpdef" class="termref">rdf-D-interpretation</a> I 
    which satisfies the semantic conditions in the following table, and satisfies all the triples in the subsequent table of <em>RDFS axiomatic triples</em>. As before, an <em>rdfs-interpretation</em>, or <em>RDFS interpretation</em>, is an rdfs-D-interpretation with D= {<code>xsd:string</code>, <code>rdf:langString</code> }.</p>
   
-<p class="issue">This table has redundancies and other problems and needs careful editing. </p>
+<p class="issue">This table has redundancies. I am inclined to leave them alone, as it takes quite a lot of thought to figure out some of the consequences when we only give non-redundant conditions. </p>
 <div class="title">RDFS semantic conditions.</div>
   <table  border="1">
     <tr> 
@@ -1236,8 +1233,8 @@
     
 <h3><a name="rdfs_entailment" id="rdfs_entailment"></a>4.4 RDFS Entailment</h3>
 <p>S <i>rdfs-D-entails</i> E when every <a href="#rdfsinterpdef" class="termref">rdfs-D-interpretation</a> 
-  which satisfies every member of S also satisfies E. RDFS entailment is RDFS-{ } entailment, i.e. RDFS-D entailment with an empty D.  </p>
-<p> Since every <a href="#rdfsinterpdef" class="termref">rdfs-interpretation</a> is an <a href="#rdfinterpdef" class="termref">rdf-interpretation</a>, if S rdfs-D-entails 
+  which satisfies every member of S also satisfies E. RDFS entailment is rdfs-{<code>rdf:langString</code>, <code>xsd:string</code> }-entailment, i.e. rdfs-D-entailment with a minimal D.  </p>
+<p> Since every <a href="#rdfsinterpdef" class="termref">rdfs-D-interpretation</a> is an <a href="#rdfinterpdef" class="termref">rdf-D-interpretation</a>, if S rdfs-D-entails 
   E then S also rdf-D-entails E; but rdfs-entailment is stronger than rdf-entailment. 
   Even the empty graph has a large number of rdfs-entailments which are not rdf-entailments, 
   for example all triples of the form </p>