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RE: RDF Graph questions

From: Dan Brickley <danbri@w3.org>
Date: Fri, 24 May 2002 08:55:38 -0400 (EDT)
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
cc: <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.LNX.4.30.0205240853430.24106-100000@tux.w3.org>


On Fri, 24 May 2002, Jeremy Carroll wrote:

> > On Fri, 24 May 2002, Jeremy Carroll wrote:
> >
> > > <rdf:RDF>
> > >  <rdf:Description rdf:about="http://example.org/"/>
> > > </rdf:RDF>
> >
> > FWIW, I always mentally parse this as syntactic longhand for:
> >
> >  <rdf:RDF>
> >   <rdfs:Resource rdf:about="http://example.org/"/>
> >  </rdf:RDF>
> >
> > 'rdf:Description' is a way of saying "there is a resource and
> > it has the
> > following (URI, properties...)". But it doesn't explicitly assert the
> > 'there exists a thing and it is of rdf:type rdfs:Resource
> > bit. Which is
> > fine, cos everything's a resource, so its a pretty vacuous
> > assertion to
> > make.
>
> This differs from Dave's position I fear.
>
> If we take the rdfs schema closure of the graph corresponding to the
> given RDF/XML file then it contains two triples
>
> rdf:type rdf:type rdf:Property .
> http://example.org/ rdf:type rdfs:Resource .
>
> (according to DanB).
>
> This can be formalized within our current framework by saying that an
> RDF Graph is a set of nodes and a set of arcs, where each arc is a
> triple [ subj, pred, obj ] where subj and obj are in the set of nodes.
>
> Dave's position can be formalized as saying that an RDF Graph is a set
> of arcs, and the nodes in the graph are defined as the set of nodes in
> the arcs. Isolated nodes that do not partake in any triples are
> prohibited.
>
> I currently agree with Dave, but fear this looks like an issue.

I don't have any strong views on this. An RDF Graph is a set of
node-edge-node arcs, for sure. We've got other stuff to worry about; don't
let me comment slow things, it was really an aside on my preference for
rdfs:Resource typedNodes over rdf:Description.

Dan
Received on Friday, 24 May 2002 08:56:41 EDT

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