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Re: raised in comment: owl:class still needed? Does this effect Test LC?

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 22 May 2003 09:15:39 -0400 (EDT)
Message-Id: <20030522.091539.125108671.pfps@research.bell-labs.com>
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org

From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: raised in comment: owl:class still needed? Does this effect Test LC?
Date: Thu, 22 May 2003 09:03:25 -0400

> At 8:23 AM -0400 5/22/03, Peter F. Patel-Schneider wrote:
> >From: Jim Hendler <hendler@cs.umd.edu>
> >Subject: raised in comment: owl:class still needed? Does this effect Test LC?
> >Date: Wed, 14 May 2003 11:19:38 -0400
> >
> >>
> >>  One part of one of our public comments from RDF Core asks:
> >>
> >>  RDFCore: Comments on OWL Reference
> >>  http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0004.html
> >>
> >>     #owlref-rdfcore-owl-class-denotation
> >>     It has been suggested to
> >>     RDFCore that owl:Class is not needed.  RDFCore requests the
> >>     creation of test cases to clearly illustrate the differences
> >>     between owl:Class and rdfs:Class.
> >>
> >>  I'd like to see such a test (or tests) in our LC Test document, as it
> >>  is likely that we will get this same or similar comment again.  If
> >>  such a test cannot be generated, then I believe we need to reopen
> >>  issue 5.20 as it was determined at the Bristol f2f:
> >>
> >>    re 5.20 Should OWL provide synonyms for RDF and RDFS objects? no,
> >>  owl should not have synonyms; owl:Class is not a synonym.
> >>
> >>  (this is part of a long thread and the resolution included this and
> >>  other statements, but I believe the above is where the WG officially
> >>  agreed owl:class was not a synonym)
> >>
> >>  and appropriately change our documents.
> >>
> >>  Peter/Ian (or anyone else) - can one of you remind the WG the
> >>  difference and design a test case for it?
> >
> >[copied out of another message]
> >
> >The RDFS-compatible semantics for OWL DL heavily depends on owl:Class (more
> >precisely, on IOC, the class extension of owl:Class).  If the distinction
> >between owl:Class and rdfs:Class was removed the semantics would be quite
> >different.
> >
> >Test cases are rather hard to come by, as OWL DL is designed so as to
> >prevent one from interacting with classes that are not OWL classes.
> >
> >However, if one looks at RDF graphs that are not in OWL DL one can see the
> >difference.  For example,
> >
> >ex:a rdf:type rdfs:Class .
> >ex:ia rdf:type ex:a .
> >
> >currently does not OWL DL entail
> >
> >ex:ia rdf:type _:i .
> >_:i owl:intersectionOf _:l1 .
> >_:l1 rdf:type rdf:List .
> >_:l1 rdf:first ex:a .
> >_:l1 rdf:rest rdf:nil .
> >
> >but it would if owl:Class was replaced with rdfs:Class in the semantics.
> >
> >peter
> 
> Looks good.  What about another one that somehow reflects that 
> rdfs:[C]lass is a member of rdfs:[C]lass, but owl:[C]lass is not a member 
> of owl:[C]lass?

Also possible.  I was tyring to get away from using the built-in
vocabulary, as one could just special case it all.

peter
Received on Thursday, 22 May 2003 09:15:49 GMT

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