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Re: pfps-05 RDFS closure rules [not complete yet]

From: pat hayes <phayes@ihmc.us>
Date: Thu, 31 Jul 2003 18:40:46 -0500
Message-Id: <p06001a62bb4f57b7d953@[10.0.100.23]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: bwm@hplb.hpl.hp.com, www-rdf-comments@w3.org

>I believe that the rules for rdfs entailments are still incomplete in the
>current version of RDF Semantics (Editors [sic] Draft July 27).
>
>For example, consider the RDF graph
>
>	ex:foo ex:bar "<"^^rdf:XMLLiteral .
>	ex:bar rdfs:range rdf:XMLLiteral .
>
>I believe that this graph has no rdfs-intepretations

Yes, you are right. I had overlooked this case; and the proof 
implicitly assumes that XML literals are wellformed.

I will modify the statement of the RDFS entailment lemma so as to 
exclude such cases, by requiring the antecedent to be consistent. I 
will also add explanatory text to section 5, which has a paragraph
which curently ends:
"An ill-typed literal does not in itself constitute an inconsistency, 
but a graph which entails that an ill-typed literal has rdf:type 
rdfs:Literal would be inconsistent."

to be modified to:

"An ill-typed literal does not in itself constitute an inconsistency, 
but a graph which entails that an ill-typed literal has rdf:type 
rdfs:Literal, or that an ill-typed XML literal has rdf:type 
rdf:XMLLiteral, would be inconsistent."

Thanks for catching this.

Pat


>  and thus that it
>rdfs-entails
>
>	rdf:type rdf:type rdf:type .
>
>which I believe cannot be deduced from the RDFS entailment rules.
>
>peter
>
>
>
>From: pat hayes <phayes@ihmc.us>
>Subject: Re: pfps-05 RDFS closure rules
>Date: Tue, 29 Jul 2003 02:27:55 -0500
>
>>  >From: Brian McBride <bwm@hplb.hpl.hp.com>
>>  >Subject: pfps-05 RDFS closure rules
>>  >Date: 28 Jul 2003 16:28:28 +0100
>>  >
>>  >>  Peter,
>>  >>
>>  >>  This message concerns a last call comment you raised on the RDFCore
>>  >>  semantics document recorded as:
>>  >>
>>  >>  http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-05
>>  >>
>>  >>  Since the WG first responded to this comment
>>  >>
>>  >> 
>>http://lists.w3.org/Archives/Public/www-rdf-comments/2003AprJun/0185.html
>>  >>
>>  >>  the semantics document has undergone further refinement and I would like
>>  >>  to check with you whether the current editor's draft
>>  >>
>>  >>    http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-mt-20030117/
>>  >>
>>  >>  is a satisfactory disposition of your comment.  Please, as usual, copy
>>  >>  www-rdf-comments@w3.org on your reply.
>>  >>
>>  >>  Brian
>>  >
>>  >Unfortunately, this document still has problems with the RDF and RDFS
>>  >entailment rules.  The problems are less critical because the status of the
>>  >RDFS entailment rules have been further downgraded.
>>  >
>>  >Currently the document states ``This terminology is agnostic as to whether
>>  >XML data is considered to be identical to a character string''  (Section
>>  >3).  It also states that ``The document also describes complete sets of
>>  >inference rules corresponding to the semantics de[s]cribed in the text''
>>  >(Section 0.1).
>>
>>  Peter:
>>
>>  Further to a WG decision on Friday, we have agreed that this
>>  agnosticism is inappropriate; the semantics now insists that the
>>  denotata of rdf:XMLliteral typed literals, and plain literals, are
>>  never the same.  The wording you cite above has been replaced with:
>>
>>  "Any character string sss which satisfies the conditions for being in
>>  the lexical space of rdf:XMLLiteral will be called a well-typed XML
>>  literal string. The corresponding value, i.e. the Canonical XML data
>>  corresponding to a well-typed XML literal, will be called the XML
>>  value of the literal.  Note that the XML  values of well-typed XML
>>  literals are in precise 1:1 correspondence with the XML literal
>>  strings of such literals, but are not themselves character strings."
>>
>>  Pat
>>  --
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Received on Thursday, 31 July 2003 19:40:52 GMT

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