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

From: Jim Hendler <hendler@cs.umd.edu>
Date: Thu, 22 May 2003 09:03:25 -0400
Message-Id: <p05200f0dbaf27adf60c5@[195.111.109.23]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-webont-wg@w3.org

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:class is a member of rdfs:class, but owl:class is not a member 
of owl:class?

-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
http://www.cs.umd.edu/users/hendler
Received on Thursday, 22 May 2003 09:03:44 GMT

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