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Re: 5.20, need for synonyms

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 26 Jul 2002 22:32:40 -0400
To: jonathan@openhealth.org
Cc: www-webont-wg@w3.org
Message-Id: <20020726223240C.pfps@research.bell-labs.com>

From: "Jonathan Borden" <jonathan@openhealth.org>
Subject: Re: 5.20, need for synonyms
Date: Fri, 26 Jul 2002 19:20:08 -0400

> Peter F. Patel-Schneider wrote:
> > From: "Jonathan Borden" <jonathan@openhealth.org>
> > Subject: 5.20, need for synonyms
> > Date: Fri, 26 Jul 2002 16:05:31 -0400
> >
> > >
> > > Let me state my position for the archives:
> > >
> > > If any concept, token, QName or URIreference is defined _exactly_ as in
> > > RDF/RDFS it is correct to use the rdf/rdfs namespace.
> > >
> > > If any concept/token/QName or URIreference is defined _in any small or even
> > > trivial_ way differently for OWL than RDF/RDFS, then this concept should be
> > > given a name in the OWL namespace.


> For example, rdf:Property becomes an instance of rdfs:Class in
> > RDFS.
> I've not seen a good explanation for why one is in "rdf" and the other in
> "rdfs" ... I'd not like to propogate mistakes.

And how are we supposed to fix this mistake, if mistake it is?

> > In fact, I don't think that this position is tenable at all, partly to do
> > with differences like the one mentioned just above.  For example, every
> > resource belongs to owl:Thing, so the meaning of every resource is changed
> > (perhaps) trivially in this way.
> Perhaps that is a subtly different issue.
> Is the meaning of <rdf:Resource> changed when OWL asserts:
> rdf:Resource rdfs:subClassOf owl:Thing .

Well, as I don't think that it matters, so I'm not interested in the answer
to the question.

> Perhaps we are dealing with an inherently non-monotonic system....

No.  Adding is monotonic.

> In any case do you intend that:
> A:
> ex:foo rdf:type rdfs:Class
> entails
> ex:foo rdf:type owl:Class

Well daml:Class is special in that it has a different meaning from
rdfs:Class, so I would say that if one is interested in owl:Class then no.

> B: would it be acceptable to replace all occurances of the token "owl:Class"
> with "rdfs:Class"?

See above.

> C: Would it be possible to refer anyone seeking a definition of an OWL Class
> to the RDFS documentation?

Again, no, because if one cares, daml:Class (and thus probably owl:Class)
is different from rdfs:Class.

> > The objection that belonging to owl:Thing is not part of the definition of
> > a resource founders on just what is the definition of a resource.
> Just so. When encountering a QName, one ought be able to dereference the
> namespace URI and retrieve a document into which one can find a definition
> by using the QName local-name as an identifier e.g.

How can this be done?  RDF does not have namespaces or localnames, just URI
references.  See the recent discussion in the RDF Core WG on this.

Further, there is no notion of a definition in RDF, just statements.
Similarly OWL has no notion of a definition.  What is a definition?  How
will you be able to find (all of) it?  The very idea of a definition seems
to go against the RDF vision.

> http://example.org/ns#foo
> =>
> <html>
> ...
> <div id="foo">
> <h3>foo</h3>
> <p>The <code>foo</code> ...
> so is there any reason for someone to look into OWL documentation to see how
> a "Class" is being defined? If so => owl:Class

> Jonathan

Received on Friday, 26 July 2002 22:32:48 UTC

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