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Re: revised version of semantics document

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 23 Aug 2002 23:31:34 -0400 (EDT)
Message-Id: <20020823.233134.125123803.pfps@research.bell-labs.com>
To: jos.deroo.jd@belgium.agfa.com
Cc: www-webont-wg@w3.org

From: "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>
Subject: Re: revised version of semantics document
Date: Sat, 24 Aug 2002 03:02:30 +0200

> [...]
> 
> > > > Why should anyone care at all about the entailment rules?
> > >
> > > because
> > >
> > [...]
> >
> > OK, agreed, entailment can be related to *inference* rules.
> >
> > But why should I care whether ``no new existentials are introduced in the
> > [inference] rules''?
> 
> OK, e.g. we can't have existentials in the conclusion that are
> in the domain of an owl:InverseFunctionalProperty because that
> property is simply not defined over it's whole range
> (lists in the range of e.g. owl:intersectionOf could contain a
> mix of resources being classes, properties, classes/properties
> and so many of such intersections simply don't exist and in
> general we can't give the list constraints in the premis)

Why not?  You mean, perhaps, that you can't.

However, there is nothing to prevent one from writing an inference rule
like

                ?x rdf:type owl:Class .
		?y rdf:type owl:Class .
	        ?i rdf:type ?x . 
	        ?i rdf:type ?y.
	implies ?i rdf:type _:l .
		_:l owl:intersectionOf [ ?x ?y ] .

peter
Received on Friday, 23 August 2002 23:31:46 GMT

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