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Re: Issue: Add hasValue to OWL Lite

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Mon, 9 Dec 2002 20:09:11 +0000
Message-ID: <15860.63591.647739.477661@merlin.horrocks.net>
To: Deborah McGuinness <dlm@ksl.Stanford.EDU>
Cc: www-webont-wg@w3.org

This has been overtaken by Jeremy's proposal and the resulting
discussion - see [1]

Ian

[1] http://lists.w3.org/Archives/Public/www-webont-wg/2002Dec/0054.html


On December 5, Deborah McGuinness writes:
> 
> >
> 
> In preparation for next week's discussion of hasValue, in going through the mailing list, this is the only
> written compromise solution.  My reading of this is a proposal that says:
> 
> MexicanRestaurant = (hasValue foodServing MexicanFood)
> 
> then if x is known to be an instance of mexicanRestaurant then we know that x has a value of MexicanFood
> for its foodServing slot
> 
> (i.e., inheritance works because hasValue is a necessary condition)
> 
> BUT
> if y is known to have MexicanFood for a value of its foodServing slot then we can NOT infer that y is an
> instance of MexicanRestaurant.
> (i.e., recognition does not work because hasValue is not considered to be a sufficiency condition).
> 
> this proposal means that hasValue has a different semantics than it has in DAML+OIL and we would need to
> decide what the semantics would be in OWL DL and OWL Full.
> 
> I was not on a telecon where I believe this issue may have been discussed more completely and if someone
> who was on that call can relay any consensus, that would be useful in preparation for next week's
> discussion of this issue.
> 
> 
> > Re: Issue: Add hasValue to OWL Lite
> >
> > From: Jim Hendler (hendler@cs.umd.edu)
> > Date: Thu, Oct 31 2002
> >
> > *Next message: Peter F. Patel-Schneider: "Re: Guide: draft of Oct 31 (goofy TranstiveProperty use)"
> >
> >    * Previous message: Smith, Michael K: "RE: Guide: draft of Oct 31"
> >    * In reply to: Ian Horrocks: "Re: Issue: Add hasValue to OWL Lite"
> >    * Next in thread: Jos De_Roo: "Re: Issue: Add hasValue to OWL Lite"
> >    * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
> >    * Other mail archives: [this mailing list] [other W3C mailing lists]
> >    * Mail actions: [ respond to this message ] [ mail a new topic ]
> >
> >   ------------------------------------------------------------------------
> >
> > Message-Id: <p05111710b9e759013172@[10.0.0.16]>
> > Date: Thu, 31 Oct 2002 17:05:21 -0500
> > To: Ian Horrocks <horrocks@cs.man.ac.uk>, Dan Connolly <connolly@w3.org>
> > From: Jim Hendler <hendler@cs.umd.edu>
> > Cc: Deborah McGuinness <dlm@ksl.stanford.edu>, webont <www-webont-wg@w3.org>
> > Subject: Re: Issue:  Add hasValue to OWL Lite
> >
> > At 3:45 PM +0000 10/31/02, Ian Horrocks wrote:
> > >On October 29, Dan Connolly writes:
> > >>
> > >>  On Tue, 2002-10-29 at 18:34, Ian Horrocks wrote:
> > >>  >
> > >>  > The problem with adding hasValue to OWL Lite is that it wouldn't be
> > >>  > Lite any more. The lack of hasValue in Lite is, from an implementation
> > >>  > point of view, the main thing that differentiates it from fast -
> > >>  > hasValue is very tough to deal with, and is responsible for pushing
> > >>  > the worst case complexity of reasoning in fast OWL from ExpTime to
> > >>  > NExpTime.
> > >>
> > >>  Could you unpack that a bit?
> > >>
> > >>  Could you give an example, maybe?
> > >
> > >I'm not sure. This isn't anything to do with reasoning techniques or
> > >specific examples, it is a fundamental property of the logic that
> > >basic inference problems (satisfiability, subsumption, entailment) are
> > >much harder when we add extensionally defined classes (which is what
> > >hasValue amounts to).
> > >
> > >If you want an intuition, it comes down to the loss of the tree(ish)
> > >model property. Without this property, it is very hard to devise
> > >decision procedures that work in a goal-directed way and that know
> > >when they are done.
> > >
> > >Ian
> >
> > Ian - the question arose at the Telecon as to whether this was true
> > for both the IF and the ONLY IF (i.e. hasValue -> X vs X -> hasValue)
> > -- that is, does saying "All Mexican restaurants serve Mexican food"
> > cause the problem if you're not expected to be able to say "all
> > places that serve Mexican food are Mexican restaurants"??
> >   -JH
> >
> > --
> > Professor James Hendler                           hendler@cs.umd.edu
> > Director, Semantic Web and Agent Technologies     301-405-2696
> > Maryland Information and Network Dynamics Lab.    301-405-6707 (Fax)
> > Univ of Maryland, College Park, MD 20742          240-731-3822 (Cell)
> > http://www.cs.umd.edu/users/hendler
> >
> >   ------------------------------------------------------------------------
> >
> >    * Next message: Peter F. Patel-Schneider: "Re: Guide: draft of Oct 31 (goofy TranstiveProperty use)"
> >    * Previous message: Smith, Michael K: "RE: Guide: draft of Oct 31"
> >    * In reply to: Ian Horrocks: "Re: Issue: Add hasValue to OWL Lite"
> >    * Next in thread: Jos De_Roo: "Re: Issue: Add hasValue to OWL Lite"
> >    * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
> >    * Other mail archives: [this mailing list] [other W3C mailing lists]
> >    * Mail actions: [ respond to this message ] [ mail a new topic ]
> 
> --
>  Deborah L. McGuinness
>  Knowledge Systems Laboratory
>  Gates Computer Science Building, 2A Room 241
>  Stanford University, Stanford, CA 94305-9020
>  email: dlm@ksl.stanford.edu
>  URL: http://ksl.stanford.edu/people/dlm
>  (voice) 650 723 9770    (stanford fax) 650 725 5850   (computer fax)  801 705 0941
> 
Received on Monday, 9 December 2002 14:09:03 GMT

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