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Re: ISSUE 5.3 some of the HP discussions

From: Dan Connolly <connolly@w3.org>
Date: 01 Jul 2003 16:34:54 -0500
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: www-webont-wg@w3.org
Message-Id: <1057095293.24283.1752.camel@dirk.dm93.org>

On Tue, 2003-07-01 at 13:23, Jeremy Carroll wrote:
> I drafted this before the weekend traffic concerning changing the defn of 
> owl:Thing and owl:Class in section 5.3.

I haven't been watching that very closely either...

> These discussions preceded the reopening of the issue, and resulted in us 
> deciding not to ask for the issue to be reopened.
> Summary: HP is not intending to oppose if-then layering between OWL DL and
> OWL Full,

I discussed the situation with my colleages in Semantic Web Advanced
Development at W3C, and we don't see a big problem either.

>  as reported by Peter; but would prefer a more thorough fix,
> retaining the iff in the consensus document. We are unwilling to do much
> work towards such a fix, nor would we want to see the WG delayed by months
> in such a task.
> 1) The counterexamples were surprising, and if no substantive changes are
> made, some changes will be needed so that the reader of the OWL documents
> will be less surprised.
> 2) Peter says:
>  >However, this does not violate any of the claims in S&AS, as the relevant
>  >theorem is that if an entailment holds in OWL DL then it holds in OWL Full,
>  > not vice versa.
> Seems reasonable, weaker than we realized, but reasonable.
> 3) It violates the concensus statement:
>       "KB large-OWL-entails C  iff  KB Fast-OWL-entails C"
> but its not so clear that it fails to satisfy the original issue.
> The original issue required layering on RDF/RDFS which OWL Full
> achieves. OWL/DL is, in any case, not part of that original requirement
> through not being an RDF/RDFS supserset.
> Having entailments over OWL/DL be only a proper subset of the OWL Full
> entailments doesn't feel like it makes matters that much worse.

That's pretty much the conclusion we came to as well.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 1 July 2003 17:49:14 UTC

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