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Re: What is an OWL document? was: Re: SEM: Light review of semantics document

From: Dan Connolly <connolly@w3.org>
Date: 20 Nov 2002 08:52:38 -0600
To: Jonathan Borden <jonathan@openhealth.org>
Cc: Jim Hendler <hendler@cs.umd.edu>, Pat Hayes <phayes@ai.uwf.edu>, www-webont-wg@w3.org
Message-Id: <1037803960.1581.61.camel@jammer>

On Tue, 2002-11-19 at 21:53, Jonathan Borden wrote:
> pat hayes wrote:
> > >
> > >Chris/Pat - I think you guys misunderstood me - I believe that all
> > >of these things are OWL documents, but I'm concerned with a small
> > >matter of usage.  The way I see it, there are documents which are
> > >clearly owl ontologies because they define terms and properties and
> > >the like. There are also owl documents that only use those terms
> >
> > There are also RDF and RDFS documents that use those terms. So? I
> > thought y'all *wanted* things to work out that way, that is supposed
> > to be part of the layercake, right? So that people can use these
> > languages together all nice and smoothly. That's why we went to all
> > this trouble in the model theory.... Do you have a problem with this,
> > now??
> >
> > >and, in fact, there is no reason that there will be any trace of any
> > >OWL vocabulary in those documents.
> >
> > Well then they won't be OWL documents. They will be be, say, RDF
> > documents that use a vocabulary defined (yech, I hate that word) in
> > another document that uses OWL.
> >
> I'd like to suggest that (assuming document's which have legal RDF/XML
> syntax);
> Documents served with a media type: application/rdf+xml
> 1) are RDF documents
> 2) might be OWL documents
> Documents served with a media type: application/owl+xml
> 1) are OWL documents
> 2) are RDF documents
> That is to say: an OWL document is an RDF document which is interpreted
> according to the OWL semantics.

Er... again, how you look at a document doesn't change the identity
of a document, and thus doesn't distinguish a document from
being an owl document or not; the interpretation/entailment/semantics
things aren't one-place predicates, ala OWL(x) vs. RDF(x),
but rather two-place relations: owl-entails(x,y) vs. rdf-entails(x,y).

If anybody thinks there are documents that are RDF documents that
are not OWL documents, please (a) give an example, and
(b) point to the part of our spec that specifies that it's
not an OWL document. Because I consider any such material
in our specs a bug and I intend to fix it.

There are documents that are rdf-consistent but not owl-consistent,
but being inconsistent doesn't take a document out of
the class of owl documents.

The OWL DL and OWL Lite dialects have syntactic limitations,
but OWL Full does not.

> Jonathan
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 20 November 2002 09:52:43 UTC

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