author Pat Hayes Fri, 01 Mar 2013 15:14:19 -0600 changeset 616 e57ebaf12a77 parent 615 48d039abc4af child 617 44085a70b843 child 622 5de7a3a4b6d3
no message
 rdf-mt/index.html
```--- a/rdf-mt/index.html	Fri Mar 01 13:40:28 2013 -0600
+++ b/rdf-mt/index.html	Fri Mar 01 15:14:19 2013 -0600
@@ -664,7 +664,7 @@
<tr>
<td class="semantictable"><p>if E is a ground triple s p o<code>.</code>
then I(E) = true if </p>
-        <p>s, p and o are in V, <span >I(p) is in IP and the pair </span> &lt;I(s),I(o)&gt;
+        <p>I(p) is in IP and the pair </span> &lt;I(s),I(o)&gt;
is in IEXT(I(p))</p>
<p>otherwise I(E)= false.</p></td>
</tr>
@@ -692,7 +692,7 @@

<p class="issue">The Concepts document does not yet define blank node scopes.</p>

-<p> Suppose I is an interpretation and A is a mapping from a set of blank nodes to the universe IR of I. Define the mapping [I+A] to be I on names, and A on blank nodes on the set: [I+A](x)=I(x) when x is a name and [I+A](x)=A(x) when x is a blank node; and extend this mapping to triples and RDF graphs using the rules given above for names. </p>
+<p> Suppose I is an interpretation and A is a mapping from a set of blank nodes to the universe IR of I. Define the mapping [I+A] to be I on names, and A on blank nodes on the set: [I+A](x)=I(x) when x is a name and [I+A](x)=A(x) when x is a blank node; and extend this mapping to triples and RDF graphs using the rules given above for ground graphs. </p>

<div  class="title">Semantic condition for blank nodes.</div>
<table cellpadding="5" border="2" summary="Semantic conditions for blank nodes">
@@ -712,7 +712,7 @@
<h3>Intuitive summary</h3>

<p>An RDF graph is true exactly when:</p>
-<p>1. the IRIs and literals in subject or object position in the graph all refer to actual things,</p><p> 2. string literals and language-tagged strings refer to their own lexical forms, </p><p>3. there is some way to interpret all the blank nodes in the scope as referring to actual things,</p><p>4. the IRIs in property position identify binary relationships,</p><p>5. and, under these interpretations, each triple S P O in the graph asserts that the thing referred to as S, and the thing referred to as O, do in fact stand in the relationship identified by P. </p>
+<p>1. the IRIs and literals in subject or object position in the graph all refer to things,</p><p>2. there is some way to interpret all the blank nodes in the scope as referring to things,</p><p>3. the IRIs in property position identify binary relationships,</p><p>4. and, under these interpretations, each triple S P O in the graph asserts that the thing referred to as S, and the thing referred to as O, do in fact stand in the relationship identified by P. </p>

<p>All semantic extensions of any vocabulary or higher-level notation encoded in RDF <a class="RFC2119">MUST</a> conform to these minimal truth conditions. Other semantic extensions may extend and add to these, but they <a class="RFC2119">MUST NOT</a> over-ride or negate them. </p>

@@ -833,14 +833,17 @@

<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> A literal whose datatype IRI is recognized, but whose character string is not in the domain of the datatype mapping, is called <em>ill-typed</em>.</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>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>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, even though no L2V mapping is defined for it. 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> 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>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 which is normatively defined to identify a datatype, as referring to that datatype. In particular, the XML Schema built-in datatype IRIs listed in <a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/#xsd-datatypes">///Concepts 5.1///</a> <strong class="RFC2119">MUST</strong> refer to the datatypes defined in ///XML Schema///, the IRI <code>rdf:HTML</code> <strong class="RFC2119">MUST</strong> refer to the datatype described in <a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/#section-html">///Concepts 5.2///</a>, the IRI <code>rdf:XMLLiteral</code> <strong class="RFC2119">MUST</strong> refer to the datatype described in <a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/#section-XMLLitera">///Concepts 5.3///</a>, and the IRI <code>rdf:plainLiteral</code> <strong class="RFC2119">MUST</strong> refer to the datatype defined in <a href="www.w3.org/TR/rdf-plain-literal/">///PlainLiteral///</a>. </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>

<h3>D-interpretations</h3>
@@ -872,11 +875,11 @@
<p>Several of the basic properties of simple entailment are also true for D-entailment, but the <a href="#interplemma" class="termref">interpolation lemma</a> is not true for D-entailment, since D-entailments
can hold because of particular properties of the lexical-to-value mappings of the  recognized datatypes. For example, if D contains <code>xsd:number</code> then </p>

-<p><code>aaa ppp "00025"^^xsd:number .</code></p>
+<p><code>aaa ppp "00025"^^xsd:integer .</code></p>

<p>D-entails</p>

-<p><code>aaa ppp "25"^^xsd:number .</code>
+<p><code>aaa ppp "25"^^xsd:integer .</code>
</p>
<p>
<p>Ill-typed literals are the only form of simple D-contradiction, but datatypes can give rise to a variety of other contradictions when combined with the RDFS vocabulary, defined later.</p>
@@ -896,8 +899,7 @@
<td class="semantictable"><a name="rdfsemcond1" id="rdfsemcond1"></a>x is
in IP if and only if &lt;x, I(<code>rdf:Property</code>)&gt; is in IEXT(I(<code>rdf:type</code>))</td>
</tr>
-<tr><td class="semantictable"><a name="rdfsemcond2" id="rdfsemcond2"> For every language-tagged string E, &lt; I(E), I(<code>rdf:langString</code>) &gt; is in IEXT(I(<code>rdf:type</code>))
-<tr><td class="semantictable"><a name="rdfsemcond3" id="rdfsemcond3">For every other IRI aaa in D, and every well-typed literal "sss"^^aaa, &lt; IL("sss"^^aaa), I(aaa) &gt; is in IEXT(I(<code>rdf:type</code>))</td></tr>
+<tr><td class="semantictable"><a name="rdfsemcond3" id="rdfsemcond3">For every IRI aaa in D, &lt; x, I(aaa) &gt; is in IEXT(I(<code>rdf:type</code>)) if and only if x is in the value space of I(aaa)</td></tr>

</tbody>
@@ -940,11 +942,11 @@

<p> The last semantic condition in the above table gives entailments of this form for recognized datatypes: </p>

-<p><code>aaa ppp "nnn"^^xsd:number .</code></p>
+<p><code>aaa ppp "123"^^xsd:integer .</code></p>

-<p>rdf-{<code>xsd:number</code>}-entails</p>
+<p>rdf-{<code>xsd:integer</code>}-entails</p>

-<code>aaa ppp _:x . <br/> _:x rdf:type xsd:number .</code>
+<code>aaa ppp _:x . <br/> _:x rdf:type xsd:integer .</code>

</p>

@@ -997,6 +999,7 @@
<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>
<div class="title">RDFS semantic conditions.</div>
<table  border="1">
<tr>
@@ -1139,7 +1142,7 @@

<p>Since I is an <a href="#rdfinterpdef" class="termref">rdf-interpretation</a>, the first condition implies that IP
= ICEXT(I(<code>rdf:Property</code>)).</p>
- <p>The semantic conditions on rdf-D-interpretations, together with the RDFS conditions on ICEXT, mean that every recognized datatype can be treated as an RDFS class, whose extension contains all the datatype values which are in the range of the datatype L2V mapping: ICEXT(I(aaa)) = { x : x = L2V(I(aaa))(sss) } for some string sss, when aaa is a datatype IRI in D. </p>
+ <p>The semantic conditions on rdf-D-interpretations, together with the RDFS conditions on ICEXT, mean that every recognized datatype can be treated as an RDFS class, whose extension is the value space of the datatype: ICEXT(I(aaa)) = {&nbsp;x&nbsp;:&nbsp;x=L2V(I(aaa))(sss) for some string sss&nbsp;} , when aaa is a datatype IRI in D. </p>
<p>These axioms and conditions have some redundancy. For example, all but one
of the RDF axiomatic triples can be derived from the RDFS axiomatic triples
and the semantic conditions on ICEXT,<code> rdfs:domain</code> and <code>rdfs:range</code>.
@@ -1238,8 +1241,8 @@
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>
-<p> <code>xxx rdf:type rdfs:Resource .</code></p>
-<p>are true in all <a href="#rdfsinterpdef" class="termref">rdfs-interpretation</a>s.</p>
+<p> <code>aaa rdf:type rdfs:Resource .</code></p>
+<p>where aaa is an IRI, are true in all <a href="#rdfsinterpdef" class="termref">rdfs-interpretation</a>s.</p>

<h2><a name="MonSemExt" id="MonSemExt"></a>6. Monotonicity of semantic extensions ```