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Re: proposal for working on the ontology language

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 11 Dec 2001 13:46:03 -0500
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org
Message-Id: <20011211134603W.pfps@research.bell-labs.com>
From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: proposal for working on the ontology language
Date: Tue, 11 Dec 2001 13:30:40 -0500

> At 11:27 AM -0500 12/11/01, Peter F. Patel-Schneider wrote:
> >
> >
> >2/ Syntax
> >
> >    Changes to the model theory for DAML+OIL may make a different syntax for
> >    DAML+OIL more attractive, or, alternatively, make the current syntax
> >    less attractive.  I think that it would be better to divide DAML+OIL
> >    into two parts---the RDF part and the non-RDF part.  The RDF part would,
> >    I think, best retain the RDF syntax, but the non-RDF part might be
> >    better put in a different syntax.
> >
> 
> Peter - this is an interesting idea, perhaps you could give a short 
> precis to the group as to what you have in mind.

I'm not sure that I can make it short, but here goes.

Suppose you have the need to represent a disjunctive concept.  In DAML+OIL
this is easy, just

<daml:Class rdf:about="#Person">
  <daml:disjointUnionOf rdf:parseType="daml:collection">
    <daml:Class rdf:about="#Man"/>
    <daml:Class rdf:about="#Woman"/>
  </daml:disjointUnionOf>
</daml:Class>

However, the definition of Person is not really RDF.  In fact, if we want
to be upwardly compatible with RDF(S) entailment then the triples that
encode disjointUnionOf cannot end up in the RDF model theory.

(Why?  Well if they do then we don't get the entailment of 

<daml:Class rdf:about="#Person">
  <daml:disjointUnionOf rdf:parseType="daml:collection">
    <daml:Class rdf:about="#Woman"/>
    <daml:Class rdf:about="#Man"/>
  </daml:disjointUnionOf>
</daml:Class>

)

Given that the encoding of the disjointUnionOf doesn't end up having any
RDF meaning, it might make more sense to use a different syntax, perhaps
something like

<daml:Class rdf:about="#Person">
  <daml:disjointUnionOf>
    <daml:Class rdf:about="#Woman"/>
    <daml:Class rdf:about="#Man"/>
  </daml:disjointUnionOf>
</daml:Class>


peter
Received on Tuesday, 11 December 2001 13:47:11 GMT

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