W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > January 2002

Re: RDF datatyping

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Thu, 10 Jan 2002 10:27:50 +0200
To: ext Graham Klyne <GK@NineByNine.org>, Sergey Melnik <melnik@db.stanford.edu>
CC: RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <B8631D26.B548%patrick.stickler@nokia.com>
On 2002-01-07 20:54, "ext Graham Klyne" <GK@NineByNine.org> wrote:

> Sergey,
> 
> I've just looked through your 14-Dec datatyping document, and think this
> is 
> a very useful basis for discussion, and even as a proposal.
> 
> I have a few comments...
> ....
> 
> For the rest of the group, my question is this:  do we just tidy up the
> "S" 
> proposal and go with it, or do we need to discuss the alternatives?

I am strongly opposed to this (no surprise, I'm sure).

I don't see how the S proposal serves to provide a solution which the
present practices/idioms P & D (DAML) do not provide -- therefore there
is no justification for adopting what is a more complex solution for a
problem that it is already fully solved by present practices.

If the present idioms/practices did not do the job, then of course
there is justification for a new approach such as S, but since the
current idioms work fine there is no need or reason to take on yet
another approach.

The D (rdf:value/rdf:type, local) and P (rdfs:range, global) idioms do
the job just fine. 

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).

There is also the drawback that the S idioms represent a method of typing
literal labeled resources that differs from the typing of URIref labled
resources, introducing an inconsistency into RDF with regards to resource
typing in general.

Finally, if we later (e.g. in RDF 2.0) want to take a P+ approach,
(which I think is the most ideal approach once the necessary extensions
to the graph model can be made) the P and D idioms are far more
compatible with P+ than are the S idioms and therefore with P/D we
have a much easier evolution path to P+ than with S.

CONCLUSION: 

    S is a radical and unnecessary departure from the way
    data typing of literals is now done in the RDF community,
    and therefore is the least optimal choice presently on the
    table, and should not be promoted as a replacement for the
    P and D idioms.

I know that alot of work has gone into the definition and refinement of S,
and that work has certainly been invaluable in clarifying the general
understanding of what data typing means within the scope of RDF, but ...
 (I'll just shut up now ;-)

--

I sincerly think Sergey's Datatyping document is great, and
I am not objecting to the majority of its content, but only to the
S idioms as becoming the official/recommended idioms for defining
pairings of lexical form to data type (literal and data type URI).

My view is that discussion of S should be removed and descriptions
of the P and D idioms added as the currently used and now "official"
idioms for global and local literal data typing (respectively).

Am I alone in this thinking?



> I 
> think proposal "S" works pretty well.  (If the latter, we would need
> descriptions of the alternatives to match Sergey's section 4, in
> particular 
> showing how they work with the model theory.)

I agree.

I'm willing to assist in that effort as I am capable and able to do so.

Cheers,

Patrick

--
               
Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Thursday, 10 January 2002 03:27:17 EST

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