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

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 31 Jul 2003 07:04:39 -0400 (EDT)
Message-Id: <20030731.070439.123570034.pfps@research.bell-labs.com>
To: phayes@ihmc.us
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 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 07:06:12 GMT

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