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Re: Even more Fuzzy about FunctionalProperty!

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 05 Mar 2003 09:24:00 -0500 (EST)
Message-Id: <20030305.092400.63242793.pfps@research.bell-labs.com>
To: costello@mitre.org
Cc: www-rdf-logic@w3.org

From: "Roger L. Costello" <costello@mitre.org>
Subject: Re: Even more Fuzzy about FunctionalProperty!
Date: Wed, 05 Mar 2003 08:33:28 -0500

> 
> Thanks Mike.  I am not real comfortable that you have completely
> answered my question, so let me followup with the example that you
> presented.
> 
> You have stated that "hasFather" is a FunctionalProperty.  Consider
> these two instances:
> 
> <Person rdf:ID="Mike">
>     <hasFather>
>         <Person rdf:ID="Joe">
>             <age>56</age>
>         </Person>
>     </hasFather>
> </Person>
> 
> <Person rdf:ID="Mike">
>     <hasFather>
>         <Person rdf:ID="Joseph">
>             <address>101 Curl Drive, Columbus, OH</address>
>         </Person>
>     </hasFather>
> </Person>
> 
> Since "hasFather" has been declared to be a FunctionalProperty can we
> infer that this:
> 
>         <Person rdf:ID="Joe">
>             <age>56</age>
>         </Person>
> 
> is equivalent to this:
> 
>         <Person rdf:ID="Joseph">
>             <address>101 Curl Drive, Columbus, OH</address>
>         </Person>

From the premise you gave, you can infer

	  <Person rdf:ID="Joe">
	    <owl:sameIndividualAs rdf:resource="Joseph" />
	  </Person>

you can also infer

         <Person rdf:ID="Joseph">
             <age>56</age>
         </Person>

and lots of other things.

> Thus, when inferencing do we treat the values of "hasFather" as a "black
> box", or must we "reconcile" the values?  /Roger

No.  OWL has no notion of objects as black boxes, nor is such a notion
needed in OWL.  Neither does OWL have a notion of reconcilliation, nor is
such a notion needed in OWL.  It is true that an OWL will be able to infer
that Joe and Joseph denote the same individual, and thus that everything
said about Joe can also be said about Joseph.

peter
Received on Wednesday, 5 March 2003 09:24:13 GMT

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