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Re: ruleml and RDF

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 28 May 2004 11:23:55 -0400 (EDT)
Message-Id: <20040528.112355.70606890.pfps@research.bell-labs.com>
To: G.R.Wagner@tm.tue.nl
Cc: sandro@w3.org, www-rdf-rules@w3.org

From: "Wagner, G.R." <G.R.Wagner@tm.tue.nl>
Subject: RE: ruleml and RDF 
Date: Fri, 28 May 2004 16:28:24 +0200

> 
> > Sandro Hawke writes:
> > In the team comment on SWRL [1] (which is the voice of
> > the W3C staff, NOT the voice of W3C [ie the W3C member or
> > "Director"]), I wrote:
> > 
> >       SWRL connects with RDF in two ways. The crucial connections is
> >       that RDF graphs can be directly expressed in SWRL (using only
> >       the obvious syntactic transformation) and they have exactly the
> >       same meaning. 
> 
> Are you sure that this is the case?
> 
> It would require to assume OWL-Full, which doesn't seem to be very 
> popular among OWLers.
> 
> Just one issue is the question if a class has a purely extensional
> semantics, as in OWL-DL, or a kind of "intensional" semantics 
> (allowing for two classes to be different although they have the
> same extension), as in RDF and OWL-Full (and UML!).
> 
> This is a very fundamental issue, which does not depend on
> the possibility of reification.
> 
> -Gerd

The issue here is not one of OWL DL vs OWL Full.

SWRL assigns a different meaning to documents written in RDF/XML than that
provided by the RDF model theory.  

In particular, SWRL does not assign any assertional import to the triple

	ex:x1 rdf:type swrl:Variable .

As far as SWRL is concerned this triple is just part of the syntax of some
collection of SWRL rules.

Peter F. Patel-Schneider
Bell Labs Research
	
Received on Friday, 28 May 2004 11:22:29 GMT

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