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RE: The X Datatype Proposal

From: <Patrick.Stickler@nokia.com>
Date: Wed, 14 Nov 2001 23:32:54 +0200
Message-ID: <2BF0AD29BC31FE46B78877321144043114C0A0@trebe003.NOE.Nokia.com>
To: Graham.Klyne@MIMEsweeper.com
Cc: w3c-rdfcore-wg@w3.org
> >My motivation for the X proposal notation was to try
> >to get below the resource-centric graph and its
> >relation to notations and capture the knowledge
> >(statements) embodied in the graph.
> 
> Which, it seems to me is exactly what a formal semantics achieves.

Fair enough. Not being a mathematician, I can't say, but
I was certainly striving to abstract away from the resource-centric
graph view to get a better (or at least different) perspective
on the primitive bits.

> > > And there are still all the issues of how to construct a
> > > formal semantics
> > > (preferably a model theory) for your proposal, which you
> > > haven't started to
> > > do.
> >
> >Nor will I, and if that is a prerequisite for consideration,
> >then I guess that rules it out right there.
> 
> I think it is a prerequisite, because without a formal 
> semantics everything 
> else is built on sand.

Well, I meant, it is ruled out if *I* am supposed to
define the formal semantics ;-)
 
> > > (notably
> > > the distinction between subject nodes and nodes with URI
> > > labels).
> >
> >Not at all. A subject node is a node which is the value of
> >an SNode 'subject' facet. A node with a uri label is a UNode.
> >
> >The distinctions are quite explicit.
> 
> Quite.  In RDF, a node can both denote a statement *and* have 
> a URI label:
> ...
>
> Your proposal seems to preclude this.

Point taken. Quite right. That's an error of omission. There's
no reason why an SNode can't have a uriref label. Thanks for 
catching that bug.

So, in fact there isn't a conflict there.

> >So, I'm not really looking for the X proposal to be chosen
> >over the others, necessarily, but perhaps the fact that it takes
> >so different a view may be useful in understanding and evolving
> >the other proposals. Then again, maybe not...

> Well, yes, I have in the past found it useful to think about RDF in terms 
> of reified statements.  (e.g. 
> http://public.research.mimesweeper.com/RDF/RDFContexts.html.)  But I have 
> always seen any such view as being underpinned by the basic RDF triple 
> model, rather than vice versa.

But the problem arises that, in any context where you must qualify
statements (and that's darn near everywhere, really) you have to 
reify the statements, yet that is an extra step with the current
model, and should be provided IMO for free.

> It was not previously clear to me that you were not promoting this as an 
> alternative approach to handling datatyping of literals.  I suppose that, 
> at this stage of the working group life, we are really trying to converge 
> on some common concepts to present to the world.

I'm not so impractical as to expect that I can join the party
late and pick all the music ;-)

Though, if you look at the total PRO and CON scores in my
modified table that Pat made, it does get the highest score ;-)

Cheers,

Patrick
Received on Wednesday, 14 November 2001 16:32:49 EST

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