W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > July 2001

Re: A use case for anon nodes - action from telecon

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Tue, 24 Jul 2001 10:20:49 +0100 (BST)
To: pat hayes <phayes@ai.uwf.edu>
cc: Jan Grant <cmjg@mercury.ilrt.bris.ac.uk>, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.31.0107241004540.28974-100000@mail.ilrt.bris.ac.uk>
On Mon, 23 Jul 2001, pat hayes wrote:

> > My querying process is simply
> >this: the server offers to locate bits of a graph that match a pattern;
> >you describe that pattern to it using anonymous nodes as variables. Yes,
> >it might be a semantic overloading, but when I looked* there wasn't any
> >one true method for expressing queries in RDF, so I made one up.
> >
>
> I guess there is a genuine cultural clash here. Are we supposed to
> define a precise meaning for RDF, or are we supposed to take a breezy
> hack-it-up-if-we-need-it attitude to what RDF is all about? I'm quite
> happy to take either road, but we need to get the question clear,
> since the two attitudes arent really compatible. The breezy approach
> has the merit of making anything as precise as a model theory
> entirely pointless, so I would have a lot less work to do.

Let me put it another way. The query server offers a function which maps
one graph onto a sequence of graphs. The query is a graph, serialised
using RDF, which expresses the user's search criteria. It's sent wrapped
up in a query message (in other words, I suppose it's being quoted).

In other words, the query is a packaged assertion ("this represents the
things I'm looking for") and the search target performs some best-effort
processing in order to return a series of results which (it promises)
are its best effort at "answering" the query. The details of the
function it calculates are deliberately obscured.

Yes, I describe the whole think in a "hacky" fashion, but I'm not
_completely_ convinced that I'm really breaking with the spirit of RDF
here (in other words, that there's a way to describe the process I'm
performing couched in such terms that it doesn't step on the toes of a
model theory).


-- 
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
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Received on Tuesday, 24 July 2001 05:28:23 EDT

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