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Re: Possible semantic bugs concerning domain and range

From: Christopher Welty <welty@us.ibm.com>
Date: Wed, 25 Sep 2002 20:56:09 -0400
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: pat hayes <phayes@ai.uwf.edu>, www-webont-wg@w3.org, www-webont-wg-request@w3.org
Message-ID: <OF40F418F7.4BF47E0F-ON85256C40.000238CE@pok.ibm.com>

(This may sound like I'm speaking for Pat, but actually I'm trying to 
verify if I understand his position)

I think what I'm getting out of trying to ingest the discussion is that 
Pat wants the semantics of ranges to be something like, in a "free 
wheeling" syntax:

Property(p) -> EXISTS c . Class(c) AND Range(p,c)
Property(p) AND Range(p,c1) AND Range (p,c2) -> c1=c2
p(x,y) AND Range(p,c) -> c(y)

So he wants there to be one and only one class that is THE range of a 
property.   Your entailment below should still be OK, ie

Subclass(c1,c2) AND Range(p,c1) AND p(x,y)  |= c2(y)

Subclass(c1,c2) AND Range(p,c1) |= Range(p,c2)

If this is an accurate account of Pat's position, then the argument 
against the entailments in OWL regarding superclasses of property ranges 
is that it abuses the Range relation between a property and a class, and 
violates the uniqueness axiom above.


Dr. Christopher A. Welty, Knowledge Structures Group
IBM Watson Research Center, 19 Skyline Dr.
Hawthorne, NY  10532     USA 
Voice: +1 914.784.7055,  IBM T/L: 863.7055
Fax: +1 914.784.6078, Email: welty@us.ibm.com

Ian Horrocks <horrocks@cs.man.ac.uk>
Sent by: www-webont-wg-request@w3.org
09/25/2002 05:02 PM
Please respond to Ian Horrocks

        To:     pat hayes <phayes@ai.uwf.edu>
        cc:     www-webont-wg@w3.org
        Subject:        Re: Possible semantic bugs concerning domain and range



Now we seem to have a come to a better understanding about the
correspondence between FOL and OWL, could you re-answer the following



>DAML+OIL, and I hope OWL, can be viewed a fragment of FOL, with atomic
>classes and properties corresponding to unary and binary predicates
>respectively. According to this correspondence, subClassOf axioms
>become implications, e.g., A subClassOf B corresponds to:
>forall x . A(x) -> B(x)
>Similarly, a property range axiom P range A corresponds to:
>forall x,y P(x,y) -> A(y).
>What could be simpler and clearer than that?
>The combination of these two sentences entails
>forall x,y P(x,y) -> B(y).
>What could be simpler and clearer than that?
>If you want some alternative semantics, could you please explain in
>similar terms what it is?
Received on Wednesday, 25 September 2002 20:57:22 UTC

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