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Re: UPDATE: longer version of layering document

From: Leo Obrst <lobrst@mitre.org>
Date: Mon, 11 Feb 2002 16:27:10 -0500
Message-ID: <3C68372E.21FF69E2@mitre.org>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: www-webont-wg@w3.org
What's the likelihood that we could convince the RDF/S folks to consider
the effect of type in the theory, reconsider for the meta-theory? Is
there any other way of them having their cake and eating it too? Are
they aware of this issue (since Pat Hayes edited the model theory, I
guess so). If it really does affect upward languages so greatly, it may
be a "spanning" issue for the Semantic Web, as opposed to an issue just
for OWL. Worth arbitrating?


"Peter F. Patel-Schneider" wrote:
> From: Leo Obrst <lobrst@mitre.org>
> Subject: Re: UPDATE: longer version of layering document
> Date: Mon, 11 Feb 2002 10:59:37 -0500
> > Peter and Dieter,
> >
> > NIT: I don't think your example (Fig. 2) depicts what you say it should,
> > in the text following the figure, i.e., "herbivore as a class, which is
> > a sub-class of animal and disjunct to all carnivores."
> > But perhaps you intend it simply as a contentless template and we should
> > imagine the content?
> >
> > The real issue in your document is the semantic Russell-like paradox,
> > no?
> Well, more or less.
> > If Peter's one suggestion below, i.e.,
> >
> > 1/ Move rdf:type out of the theory into the metatheory
> >
> > is agreed to by the RDF/S folks, that would remove the thorniest issue,
> > no?
> >
> > Thanks,
> > Leo
> Oh yes, this would remove all of the issues!  Of course, it would be a
> *drastic* change to RDF and RDFS!  Also, it would mandate a syntax
> extension for OWL, as RDF would no longer have its metatheory accessible
> from its theory, and thus the *syntax* of RDF could not be used to access
> this metatheory.
> peter
> PS: As an aside, consider the way that XML Schema extends XML.  XML Schema
> documents use XML syntax, but don't have the same meaning as XML documents.
> This would be way of extending the syntax of RDF without extending the
> syntax of RDF.  However, the RDF access to the metatheory from the theory
> makes this way of extending RDF difficult.
> PPS:  Of course there is nothing too wrong with RDF taken by itself.
> It is just that using RDF as the basis for the semantic web is not
> possible, and it is not possible because RDF appropriates all
> syntax *and* all semantics.  (Well, it might be possible to have RDF as the
> basis, but it would be *extraordinarily* difficult and would probably
> require a complete rethink of the intended meaning of RDF.  Having RDFS as
> the basis, as RDFS is now, is, however, right out of the question.)

Dr. Leo Obrst		The MITRE Corporation
mailto:lobrst@mitre.org Intelligent Information Management/Exploitation
Voice: 703-883-6770	7515 Colshire Drive, M/S W640
Fax: 703-883-1379       McLean, VA 22102-7508, USA
Received on Monday, 11 February 2002 16:27:10 UTC

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