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Re: Moving forward

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 18 Mar 2002 22:21:28 -0500
To: jos.deroo.jd@belgium.agfa.com
Cc: phayes@ai.uwf.edu, jonathan@openhealth.org, www-webont-wg@w3.org
Message-Id: <20020318222128S.pfps@research.bell-labs.com>
From: "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>
Subject: Re: Moving forward
Date: Tue, 19 Mar 2002 00:17:25 +0100

> As an aside, I have some trouble that
>   :John a :Person .
>   :John a :Student .
> 
> would entail
>   :John a [ owl:intersectionOf ( :Person :Student ) ] .
> 
> but no trouble that it would entail
>   :John a ( owl:intersectionOf ( :Person :Student ) ) .
> 
> using
> ------------------------------------------------------------------------
> IF                             | THEN
> ------------------------------------------------------------------------
> ?x a ?a                        | ?x a ( owl:intersectionOf ( ?a ) )
> ------------------------------------------------------------------------
> ?x a ?a                        | ?x a ( owl:intersectionOf ( ?a / ?b ) )
> ?x a ( owl:intersectionOf ?b ) |
> ------------------------------------------------------------------------
> where the ( :a / :b ) is shorthand for [ owl:first :a; owl:rest :b ]
> 
> but maybe I haven't thought hard enough???
> 
> --
> Jos

The range of rdf:type is rdfs:Class, so either 

   :John a ( owl:intersectionOf ( :Person :Student ) ) .

is a contradiction (if lists and classes are disjoint), or 

   ( owl:intersectionOf ( :Person :Student ) ) a rdfs:Class .

which just gets us back to the first entailment.

So I don't think that your distinction is defensible.


Either you believe that these extra classes should exist or you believe
that they shouldn't.  About the only viable intermediate point would be to
have another category that would include restrictions and boolean class
combinations and have these exist but not have other kinds of classes
exist.

peter
Received on Monday, 18 March 2002 22:22:05 GMT

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