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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 11:01:36 -0500 (EST)
Message-Id: <20030305.110136.68531448.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 10:48:59 -0500

> 
> "Peter F. Patel-Schneider" wrote:
> > 
> > > Let the property be: lengthOf
> > >   - it maps a River to a Distance
> > >
> > > Suppose that one instance document asserts this:
> > >
> > >     The Yangtze has a lengthOf 6300 kilometers.
> > >
> > > A second instance document then asserts this:
> > >
> > >     The Yangtze has a lengthOf 3937.5 miles.
> > 
> > Well, the above is English, not OWL.  I suggest that you represent the
> > above in OWL, if possible, and then redo the example.  
> 
> It seems like perfectly good OWL to me.  Here's the definition of
> lengthOf:
> 
> <owl:DatatypeProperty rdf:ID="lengthOf">
>     <owl:type rdf:resource="http://.../owl#FunctionalProperty"/>
>     <rdfs:range rdf:resource="http://.../rdf-schema#Literal"/>
>     <rdfs:domain rdf:resource="#Stream"/>
> </owl:DatatypeProperty>
> 
> Here's an instance document that uses the lengthOf property:
> 
> <River rdf:ID="Yangtze">
>      <length>6300 kilometers</length>
> </River>
> 
> And here's a second instance document which uses the lengthOf property:
> 
> <River rdf:ID="Yangtze">
>      <length>3937.5 miles</length>
> </River>
> 
> Since lengthOf has been declared to be a FunctionalProperty I can infer:
> 
>      6300 kilometers = 3937.5 miles
> 
> Why is this not OWL?  Thanks!  /Roger

Ok, you have now represented the above information in OWL.  The particular
method that you used, however, results in an inconsistency under your
example.  You have said that an object is related to two different strings
via a functional property.

So, yes, you can infer that the two strings above co-denote, but you can
also infer that they don't.

A different representation would have different consequences.

peter
Received on Wednesday, 5 March 2003 11:01:51 GMT

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