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Re: intersectionOf and subClassOf

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 10 Apr 2003 11:32:53 -0400 (EDT)
Message-Id: <20030410.113253.103009781.pfps@research.bell-labs.com>
To: jjc@hplb.hpl.hp.com
Cc: geoff@sover.net, www-rdf-logic@w3.org

From: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Subject: RE: intersectionOf and subClassOf
Date: Thu, 10 Apr 2003 17:12:51 +0200

> 
> I think S&AS may be wrong about this.
> 
> Peter:
> [[
> Because of OWL's embedding on top of RDF there are actually several
> options that could arise here.
> 
> 1/ One could have the semantic constraint on owl:intersectionOf
> 	that if the extension of x is the same as the intersection of the
> 	extensions of a and b then x owl:intersectionOf [a b]
> 2/ One could have the semantic constraint that if
> 	   x owl:intersectionOf [a b]  then the extension of x is the same
> 	   as the intersection of the extensions of a and b
> 3/ One could have the semantic constraint that if
> 	   x owl:intersectionOf [a b]  then the extension of x is a subset
> 	   of the intersection of the extensions of a and b
> ]]
> 
> Option 1 might have been a better choice than option 2 (if I understood
> Peter's earlier message)
> 
> E.g.
> 
> Consider
> 
> <owl:Class rdf:about="#AandB">
>    <owl:equivalentClass>
>      <owl:Class>
>         <owl:intersectionOf rdf:parseType="Collection">
>           <owl:Class rdf:about="#A"/>
>           <owl:Class rdf:about="#B"/>
>         </owl:intersectionOf>
>      </owl:Class>
>    </owl:equivalentClass>
> </owl:Class>
> 
> This corresponds to the abstract syntax form
> 
> EquivalentClasses(<#AandB> intersectionOf(<#A> <#B>) )
> 
> which directly entails
> 
> Class( <#AandB> complete <#A> <#B> )
> 
> which corresponds to
> 
> 
> <owl:Class rdf:about="#AandB">
>    <owl:intersectionOf rdf:parseType="Collection">
>           <owl:Class rdf:about="#A"/>
>           <owl:Class rdf:about="#B"/>
>     </owl:intersectionOf>
> </owl:Class>
> 
> 
> i.e. option 1
> 
> but the rdfs compatible semantics has taken option 2.
> 
> Is this a bug?
> Does someone need to make a last call comment?
> Or have I misunderstood?
> 
> Jeremy

You are correct.  It is a bug, introduced when I put in the ``enhanced''
translation, and I didn't catch it when I looked at the correspondence
proofs.

peter
Received on Thursday, 10 April 2003 11:34:24 UTC

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