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Re: OWL Lite semantics

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Mon, 9 Dec 2002 20:29:09 +0000
Message-ID: <15860.64789.3517.141693@merlin.horrocks.net>
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: Jim Hendler <hendler@cs.umd.edu>, www-webont-wg@w3.org

On December 9, Jeremy Carroll writes:
> 
> I think this comment looks crucial ...
> 
> 
> > This is *NOT* simply incompleteness w.r.t. OWL DL/full semantics,
> > because a Lite reasoner would be entitled to answer NO to a question
> > about entailment when the correct DL/full answer is YES.
> 
> 
> 
> I was concentrating on the YES answers.

This is a common error.

> I will try and make a modification to the proposal that clarifies what 
> should or should not be said about entailments that are OWL Full 
> entailments but not OWL Lite entailments.

Why bother? It took us 9 months to formulate and agree to the current
semantics - is it really likely we can do the same for another
semantics between now and the proposed January last call?

I for one would vote "can't live with" on any such a proposal simply
on the grounds that it is totally unreasonable to expect the WG to
give it adequate consideration in the time available.

Ian

> 
> The intent is that they are ones that include class membership or subclass 
> relationships on the RHS.
> 
> Perhaps a different characterization should be that OWL Lite entailment 
> could be a set of pairs of documents
> 
>    A owl-lite-entails B
> 
> where A is an arbitrary owl lite document, and B uses no RDF, RDFS or OWL 
> vocabulary. i.e. owl-lite-entailment does not include any classification tasks.
> Since this is a syntactically charcaterized subset the respone of an OWL 
> Lite reasoner to does
>    X entail Y
> is
> either YES, NO, "X is not syntactically OWL Lite" or "Y involves special 
> vocabulary".
> 
> I'll think some more ...
> 
> 
> Jeremy
> 
> 
> 
> 
Received on Monday, 9 December 2002 14:29:01 GMT

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