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Re: Some basic questions about OWL-Full

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 23 Oct 2007 10:20:37 -0500
Message-Id: <p06230900c343c1429fc0@[192.168.1.2]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: jjc@hpl.hp.com, public-owl-dev@w3.org

>From: Pat Hayes <phayes@ihmc.us>
>Subject: Re: Some basic questions about OWL-Full
>Date: Tue, 23 Oct 2007 08:58:28 -0500
>
>>
>>  >Peter F. Patel-Schneider wrote:
>>  >>
>>  >>For homework:  Is EquivalentProperties(owl:sameAs owl:differentFrom)
>>  >> 	 	       itself inconsisten?
>>  >>
>>  >
>>  >I'm afraid I'm several years' late on my (easier) homework of:
>>  >    Is (*empty*) itself inconsistent?
>>
>>  Yes, in RDF (and conventional FOL). This is the
>>  only assumption of Tarskian semantic theory, that
>>  there is something in the universe. One can build
>>  a 'free' logic which allows an empty universe,
>>  but then its proof theory can't have the usual
>>  rules of instantiation and generalization, which
>>  allow the inferences
>>
>>  (forall (x) (foo x))  |==   (foo A) for some
>>  'new' name A |==  (exists (x)(foo x))
>>
>>  Pat
>
>I think Jeremy meant an empty KB, i.e., whether OWL Full is trivial or
>not.

Ah, I see. Sorry. Yes, that question amounts to 
whether the OWL semantic conditions are 
internally consistent when transcribed into 
common logic (or FOL using the holds/app style). 
Good question!

Pat

>peter


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Received on Tuesday, 23 October 2007 15:21:03 GMT

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