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RE: RDF datatyping

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Thu, 10 Jan 2002 23:21:54 -0000
To: "Graham Klyne" <GK@NineByNine.org>, "Patrick Stickler" <patrick.stickler@nokia.com>
Cc: "Sergey Melnik" <melnik@db.stanford.edu>, "RDF Core" <w3c-rdfcore-wg@w3.org>
Message-ID: <CEECKEAMDAJDDEDGJNBECEAICAAA.jjc@hpl.hp.com>
A few comments ...

Patrick:
> > The S idioms, while also doing the job, do so with more machinery and
> > most significantly are contrary to the intuitions of current RDF users
> > (data typing by predicate rather than by rdf:type).

Graham:
> I don't recognize that description of S:
> - I don't see "more machinery" here, whatever that means,
> - "contrary to the intuitions of current RDF users" is precisely one area
> where I think S scores very strongly, based on my intuitions from work
with
> CC/PP (modulo small issues raised in my comments to Sergey's paper).

The machinery I find hard to justify is:
 - Needing three URIs for each datatype.
   Seems a bit like needing to talk about "Jeremy's body", "Jeremy's soul"
and "Jeremy' mind". Might be useful sometimes, but plain "Jeremy" will get
you a long way. I suppose RDF is about triples!
 - Having two incompatible usage idioms (two compatible idioms would somehow
be less cumbersome).
 - Always carrying the lexical values in the graph, and having the lexical
values in the model theory.

I find idiom A contrary to my intuitions simply because it is very
unfamiliar, in a way that P & D are not. I find idiom B contrary in its
insistence on talking about the lexical space when what I mean is the type -
it's like a doctor who only cares about my body and not the well-being of me
as a whole.

elsewhere Patrick:
> It appears to me that the S idioms A and B are not compatible

I found that to be the intent of the current document too, and I agree that
it is a problem that the PD combination does not suffer from.

graham:
> The advantage of the S scheme is that is sits comfortably within the
> current model theory.

and again graham:
> Point me to the model theory, and I may be convinced.

I find S a theoretical work that is practically unappealling. The model
theory is the tail not the dog.

Yes, we do need a model theory to capture the PD proposal; but being
well-grounded in the model theory is not the most important consideration.
Most users will have only a passing understanding of the MT, and merely
wished to be reassured by it. If every time they think of a datatype they
need to get unnecessarily involved in the complexities of lexical spaces,
value spaces and the mappings between them they will rightly curse us.

Jeremy
Received on Thursday, 10 January 2002 18:22:26 EST

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