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Re: Issues danc-01 Re: 2 formalities in RDF concepts

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Tue, 4 Feb 2003 11:10:49 +0000 (GMT)
To: Dan Connolly <connolly@w3.org>
cc: Pat Hayes <phayes@ai.uwf.edu>, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.44.0302041106410.1699-100000@mail.ilrt.bris.ac.uk>

On Mon, 3 Feb 2003, Dan Connolly wrote:

> On Mon, 2003-02-03 at 16:13, pat hayes wrote:
> [...]
> > There are really two ways to go. We can say that RDF syntax (I'll
> > avoid the G-word for now) uses identifiers for blank nodes somehow;
> > or not, ie blank nodes are blank. If we go the first way, then the
> > concept of 'same graph' is effectively useless, since a graph with a
> > systematic change to its bound variables is semantically
> > indistinguishable from the original; and we have to talk everywhere
> > about equivalence classes of graphs, in effect, or isomorphism
> > between graphs. Also there are issues about scopes of these bound
> > variables, which we put to bed 18 months ago and which it would be a
> > chore, to put it mildly, to re-open at this stage. We decided in
> > Sebastopol to go the second route, ie to identify graphs with
> > indistinguishable blank nodes and to therefore not bother with
> > notions of renaming, bound variable and so on.
> Yes, that's the issue as I see it.
> > My own preference is that we retain the advantages of this second way
> > of doing things and re-write the concepts document wording to reflect
> > the decisions we made in Sebastopol and which we have been using as a
> > basis for our discussions ever since.
> OK by me. That was my understanding when I sent the comment
> that resulted in danc-01.
> I didn't realize we could trace it to a WG decision but upon
> review, it's pretty clear from the record:
> "It was agreed that Pat would update the model theory based on the graph
> instead of n-triples."
>  -- http://www.w3.org/2001/sw/RDFCore/20010801-f2f/
> Jan? Jeremy? Graham? Others? What say you?

I say, there are a bunch of equivalent representations of the same
thing: whether you consider "a graph" to _be_ or just to be _represented
by_ a set of triples, or an ntriples document, doesn't really make a
huge difference, except that if you start getting really pedantic about
it then you have to over-qualify the language in the statements and
proofs of all your lemmas.

In other words: avoid extra effort which provides no real benefit.

jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/
If you have received this email in error, do whatever the hell
you want with it. It's not like I can stop you anyway.
Received on Tuesday, 4 February 2003 06:13:45 UTC

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