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Re: TEST: Re: notes for 6/6 until 1:10 (oneOf/sameClassAs)

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 07 Jun 2002 20:42:18 -0400
To: connolly@w3.org
Cc: jos.deroo.jd@belgium.agfa.com, www-webont-wg@w3.org
Message-Id: <20020607204218I.pfps@research.bell-labs.com>

From: Dan Connolly <connolly@w3.org>
Subject: Re: TEST: Re: notes for 6/6 until 1:10 (oneOf/sameClassAs)
Date: 07 Jun 2002 18:51:01 -0500

> On Fri, 2002-06-07 at 17:39, Peter F. Patel-Schneider wrote:
> > From: Dan Connolly <connolly@w3.org>
> > Subject: Re: TEST: Re: notes for 6/6 until 1:10 (oneOf/sameClassAs)
> > Date: 07 Jun 2002 16:56:42 -0500
> > 
> > > 
> > > On Fri, 2002-06-07 at 16:46, Jos De_Roo wrote:
> > > [...]
> > > > > i.e. there shouldn't be any axioms with existentials in
> > > > > the conclusions. (there's a name for that fragment of FOL, no?
> > > > > is that horn clauses? I often forget).
> > > > 
> > > > All I remember for the moment is "Clause Normal Form"
> > > > and indeed no existentials in the conclusions
> > > > but functional terms could be there I think...
> > > 
> > > Functional terms and existentials buy you the
> > > same power/grief.
> > > 
> > > For OWL 1.0, I (presently) think we should stop
> > > short of that sort of thing.
> > > 
> > 
> > Stop short of what?  Functional terms?  Has anyone proposed functional
> > terms?
> 
> er... Jos mentioned them...
> > > > but functional terms could be there I think...
> 
> 
> >  Existentials?  RDF has a form of existential.  Are you proposing
> > that OWL not include blank nodes?
> 
> No, I'm proposing that, when OWL semantics are
> expressed as N3 rules

Are you seriously proposing that the semantics of a formalism be expressed
in N3?  This is like asking the fox to guard the chicken coop.

> or FOL axioms, which usually look like
>   (forall (?x ?y ?z) (if PREMISE CONCLUSION))

Well some FOL statements look like this, but not all, nor even most.

> that the conclusion shouldn't have any
> functional terms nor existentially quantified
> variables.
> i.e. there are no axioms that conclude "there exists...".

Well there are several axioms in the DAML+OIL axiomatization that have
existentially quantified variables in the conclusion.  What should happen
to these axioms?

> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> 

peter
Received on Friday, 7 June 2002 20:42:28 GMT

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