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Re: [closed] horst-01; was: RDF Semantics: RDFS entailment lemma

From: <herman.ter.horst@philips.com>
Date: Fri, 4 Jul 2003 21:31:07 +0200
To: pat hayes <phayes@ihmc.us>
Cc: www-rdf-comments@w3.org
Message-ID: <OFF08F8E41.D135D523-ONC1256D59.006A6BD0-C1256D59.006B56D1@diamond.philips.com>

Pat,

Thank you for your message.
I'll consider the new version of the entailment lemma and the
definitions that it depends on and the proof, and expect to finish 
that next week.

Regards,
Herman

=======================================================================
Herman,

with reference to your comment
http://lists.w3.org/Archives/Public/www-rdf-comments/2003AprJun/0042.html

archived as horst-01.

First, many thanks for your close attention to the technical matters 
and your helpful comments, which have required the WG to re-examine 
several of its earlier decisions.

The WG has resolved
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0025.html
to proceed as follows.

The RDS semantic conditions on subClassOf and subPropertyOf have been 
weakened to be 'only if' rather than 'iff' conditions; under these 
conditions, the entailments that you noted are no longer valid.

Details can be checked in the current editor's draft at 
http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html#rdfs_interp 
The document mentions the stronger (iff) conditions under the heading 
'extensional semantic conditions'
http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html#ExtensionalDomRang
, and describes some inference rules which are valid under these 
stronger conditions, including rules which cover the case you describe
http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html#RDFSExtRules
; but it does not claim to offer a complete set of such rules for 
these stronger conditions.

A proof of the completeness of the (somewhat shortened) list of RDFS rules
http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html#RDFSRules
  WRT the weakened semantic conditions is provided in appendix B
http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html#prf
. As you will see, most of the complexity of the proof has to do with 
the treatment of literals; the RDFS rules correspondence is now 
straightforward since all the semantic conditions map directly into 
forward implications.

Please reply to this message, copying www-rdf-comments@w3.org, 
indicating whether this response addresses your comment adequately.

Sincerely

Pat Hayes



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Received on Friday, 4 July 2003 15:32:30 GMT

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