- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Fri, 22 Feb 2002 06:10:40 -0500
- To: phayes@ai.uwf.edu
- Cc: dieter@cs.vu.nl, www-webont-wg@w3.org
Here is, I think, a major point of difference between our views of how OWL has to work. From: Pat Hayes <phayes@ai.uwf.edu> Subject: Still no paradox (was: Re: The Peter paradox isn't.) Date: Thu, 21 Feb 2002 20:23:32 -0600 [...] > >3/ Next consider DAML+OIL restrictions. > > > > If John has a child that is a Person, then John belongs to the > > Restriction that requires that its members have a child that is a > > Person. > > > > <John, child, Joe>, <Joe, rdf:type, Person> > > |= <John, rdf:type, :_1>, <:_1, rdf:type, owl:Restriction>, > > <:_1, owl:onProperty, child>, <:_1, owl:hasClass, Person> > > > > This is only a valid entailment if all satisfying OWL interpretations of > > the first two statements contain a restriction of the above form. > > True, but this does not capture the intuitive meaning of your > example. What this says in RDF is that If John has a child that is a > Person, then a Restriction *exists* such that John belongs to.... > There is however no reason why it has to make that claim in OWL. Why > would OWL want to assert the *existence* of restrictions? Thats like > having FOL assert the existence of its own formulae. I claim that this precisely captures the intuitive meaning of my example. Given an OWL KB, I need to be able to determine if an object in that KB satisfies a restriction that is not necessarily mentioned in the KB. I would be prepared to do this somewhat indirectly, as in <John, child, Joe>, <Joe, rdf:type, Person> |= <John, rdf:type, :_2>, <:2, owl:sameAs?, :_1>, <:_1, owl:onProperty, child>, <:_1, owl:hasClass, Person> However, I view any approach that does not come up with some way of doing the above as fundamentally broken. peter
Received on Friday, 22 February 2002 06:11:40 UTC