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RE: intersectionOf and subClassOf

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Thu, 10 Apr 2003 17:12:51 +0200
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, <geoff@sover.net>
Cc: <www-rdf-logic@w3.org>
Message-ID: <BHEGLCKMOHGLGNOKPGHDIEHKCBAA.jjc@hpl.hp.com>


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
Received on Thursday, 10 April 2003 11:13:21 GMT

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