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

From: pat hayes <phayes@ihmc.us>
Date: Wed, 2 Jul 2003 18:05:17 -0500
Message-Id: <p0600122bbb2913c523e0@[10.0.100.7]>
To: herman.ter.horst@philips.com
Cc: www-rdf-comments@w3.org


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conditions, the entailments that you noted are no longer valid.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 Wednesday, 2 July 2003 19:05:20 GMT

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