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Re: Model-specific identity for anon resources, and its representation: A new issue?

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Thu, 14 Jun 2001 11:41:40 +0100 (BST)
To: "jos.deroo.jd" <jos.deroo.jd@belgium.agfa.com>
cc: w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.31.0106141136280.27373-100000@mail.ilrt.bris.ac.uk>
On Thu, 14 Jun 2001 jos.deroo.jd@belgium.agfa.com wrote:

> We can imagine that anounymous terms are identified 'by their content'
> e.g. see "more N-triples (Was RDF Statements as floating Cons Cells)"
> http://lists.w3.org/Archives/Public/www-rdf-logic/2001Jun/0191.html
> elaborating on that
> [[[
>   If an arc points to an anonymous term, then it
>   is there 'by value' so to speak (not 'by reference').
>   Of course one could point to constant terms
>   and universally quantified terms used in those
>   subgraphs, but they are 'leafs' or at the 'subgraph
>   boundaries' so to speak.
> ]]]

This is not my intuition on this. I'm thinking purely of a graph-based
RDF model (for the nontechnical meaning of "model"). It has nodes; some
of those are labelled with URIs, some are not. The latter are
"anonymous resources". Two distinct anonymous nodes may be in
equivalent relationships with other nodes in the graph; this does not
make them graph-theoretically equal.

Summary: an anonymous node has its own "model-specific identity". Two
anonymous nodes in an RDF graph may have "the same content" but still be
distinct.

> Let's start with
>   _:a1 <http://random.ioctl.org/#p1> _:a2 .
>   _:a2 <http://random.ioctl.org/#p2> _:a1 .
>
> If you point to _:a1 via e.g.
>   <http://random.ioctl.org/#s3> <http://random.ioctl.org/#p3> _:a1 .
> you can see how Euler copes with such content

[much Euler output snipped]

> So I think both cases are representable in RDF, no?

Forgive me, but if that is the case (and without adding additional
triples), could you show me what the serialised RDF for each case looks
like?

jan (a bit slow on the uptake)

-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287163 Fax +44 (0)117 9287112 RFC822 jan.grant@bris.ac.uk
Semantic rules, OK?
Received on Thursday, 14 June 2001 06:42:10 EDT

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