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Re: Attempt to use Owl rule language to express preconditions in Congo

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Mon, 10 Nov 2003 20:03:51 -0500 (EST)
Message-Id: <200311110103.hAB13pw16487@pantheon-po01.its.yale.edu>
To: public-sws-ig@frink.w3.org


   [Drew McDermott]
   > Here's how I would change it:
   > 
   >    <process:Formula>
   >        <process:conjuncts rdf:parseType="Collection">
   >            <owl:individualPropertyAtom>
   >                    <owl:propertyPredicate 
   >                               rdf:resource="&congoUserProfile;accountExists/>
   >                    <owl:argument1 rdf:about="#AcctID" />
   >                    <owl:argument2 rdf:about="#Password" />
   >            </owl:individualPropertyAtom>   
   >            <owl:individualPropertyAtom>
   >                    <owl:propertyPredicate 
   >                                rdf:resource="&congoUserProfile;creditExists/>
   >                    <owl:argument1 rdf:about="#AcctID" />
   >                    <owl:argument2 rdf:about="#CreditCardNumber" />
   >            </owl:individualPropertyAtom>   
   >        </process:conjuncts>
   >    </process:Formula>

   [David Martin]
   I believe the above is equivalent to an Horrocks/Patel-Schneider rule 
   with an empty antecedent, and the 2 property atoms in the consequent. 
   If that is true, perhaps we should just express it that way for now, so 
   as to avoid defining our own Formula class which probably will be 
   supplanted later.

   I also wonder if Ian and Peter (and the joint committee) have any plans 
   to define something like Formula (or at least "ConjunctiveFormula"), so 
   that one can write non-rule formulas a little more conveniently.

I hope that OWL Rules, or something a lot like it, is going to become
the standard.  (Assuming we can't get what's really needed, which is
to introduce non-asserted contexts into RDF.)  It would be very easy
to switch DRS over to the OWLR vocabulary, thus making it a
downward-compatible superset of OWL Rules.  Since OWL Rules gets
variables right, and encodes atomic formulas right, it would be very
easy to add explicit quantifiers and a richer zoo of atomic formula
types.

Since OWL Rules is not the standard now, I don't think we gain
anything by expressing a Formula as a rule with a missing antecedent.

                                             -- Drew

-- 
                                   -- Drew McDermott
                                      Yale Computer Science Department
Received on Monday, 10 November 2003 20:03:53 GMT

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