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Re: RDF Graph questions

From: Dan Brickley <danbri@w3.org>
Date: Fri, 24 May 2002 06:24:27 -0400 (EDT)
To: Dave Beckett <dave.beckett@bristol.ac.uk>
cc: Jeremy Carroll <jjc@hplb.hpl.hp.com>, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.LNX.4.30.0205240620360.24106-100000@tux.w3.org>
On Fri, 24 May 2002, Dave Beckett wrote:

> >>>Jeremy Carroll said:
> > Second a few questions.
> >
> > 1. Are there unattached nodes in an RDF graph?
>
> No; since we base our describe the rdf graph as triples
> as node->arc->node rather than any other form.  If this is not the
> case then N-Triples in insufficient to connect the model theory and
> syntax.
>
> > 2. Can any URI ref be a property name or must there be some associated
> > namespace?
>
> Any URI ref.

No, not _any_ URI ref.

Some URI refs don't name properties.

Arguably, all the phone: ones, all the mailto: ones, and a huge % of all
the http:// URIrefs too.

But I think I agree with (what I take to be) your general point. There are
many URIrefs that we can take as naming URIrefs which aren't (for various
reasons) going to have an RDF/XML document derferencable.

However, the fact that they name RDF properties means that they can be
used in RDF/XML instance data using the XML namespace mechanism, so in
that sense they are associated with a namespace. Or they are a namespace.
Or they can be written about using XML namespaces.

   This is pretty clear from M&S and we've mentioned this
> a few times in passing with respect to the issues related to
> writing them as qnames.
>
> (XML) Namespaces are artifacts of the RDF/XML serialization and are
> not in the current model.


Dan


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Received on Friday, 24 May 2002 06:24:33 EDT

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