how to handle DAML+OIL syntax in the RDF model theory

From: Peter F. Patel-Schneider (pfps@research.bell-labs.com)
Date: 11/30/01


From: Dan Connolly <connolly@w3.org>
Subject: Re: querying DAML+OIL syntax
Date: Fri, 30 Nov 2001 11:46:24 -0600

[...]

> I expect the "obvious extra semantic condintions" includes
> an axiom of pairs, ala
> 
> 	(forall (?f ?r)
> 	  (=> (list ?r) ((exist (?l) (and (first ?l ?f) (rest ?l ?r)))))

[...]

> > Solution:
> > 
> > It does not entail.
> > 
> > There are interpretations that satisfy the first knowledge base where the
> > denotation of a is not in any list,
> 
> not if we include an axiom of pairs ala the above.

You would need to include all DAML+OIL syntax in every interpretation,
i.e., unionOf for every list of classes, .....  I'm uncertain if this
approach would work.

However, even if it would, I have severe reservations.  I liken it to a
mechanism for including disjunction in RDF that would work something like.

1/ interpretations include all possible lists
3/ for every list that looks a formula, l,
   < l , IS(rdfb:true) > in IEXT(IS(rdf:type)) 
   iff  the formula is satisfied in the interpretation
3/ list syntax denotes the appropriate list


That is

   the interpretation of 
	[OR [p1 s1 o1] [p2 s2 p2] [p3 s3 o3]] 
   is in the class extension of rdfb:true if and only if 
	   either <IS(s1),IS(o1)> in IEXT(IS(p1), or
		  <IS(s2),IS(o2)> in IEXT(IS(p2), or
		  <IS(s3),IS(o2)> in IEXT(IS(p3)


peter


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