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Re: Datatypes [Was: Minutes telecon 26th July 2002]

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Mon, 29 Jul 2002 23:45:14 +0200
To: <w3c-rdfcore-wg@w3.org>
Message-ID: <MABBLGKMPIJFCKFGDBEPIEAHCBAA.jjc@hplb.hpl.hp.com>


Sumamry:
A short piece in defence of Patrick's account of WG decisions;
a longer piece in self-defence (against Patrick!) with a more detailed
proposal for a "no global" (but untidy) datatyping/model theory solution.

In defense of Patrick ...

Patrick:
>> This has already been rejected by the WG.
DanC:
>I don't recall any such decision.
Patrick:
>> The WG has already decided that datatyping should work by one of the
>> two proposed options,
DanC:
>which decision are you referring to here?

I think
http://www.w3.org/2001/sw/RDFCore/20020225-f2f/#d-2002-02-26-3
covers both of these. Specifically committing us to a particular version of
datatyping (supporting (A)) except in response to a particular problem with
(D) being noted as a problem.

===

In self defense ...

Patrick:
>Sorry Jeremy, but I don't see your proposal
>as constituting "substantial progress". It's a step backwards.

Substantial progress towards consensus may be a step backwards on some other
measure.

Patrick:
>Of those that chose to explicitly respond as requested to Brian's
>inquiry, there is overwhelming preference for untidy semantics
>(almost unanimous).

Not quite as overwhelming as all that, but I would hope sufficiently so to
make the WG reluctant to continue with tidy literal semantics.

Patrick:
>Most importantly, the tidy/untidy issue is as much about the model theory
as
>it is about datatypes

that's true. To punt on this would require more care.


It won't have escaped your attention that I have been a steadfast advocate
of untidy literals. As a result, at Cannes, I was in a minority that got
outvoted. After this, I tried hard to work out what were the minimal changes
needed to the WG's position to make it possible for me to no longer object.
One of the possible changes then, for me, was to drop the global idiom.

Now, you argue (and I agree) that the tables have turned. However, i still
see a minority with strongly felt opinions. My understanding of the
consensus process is that we should avoid steam-rollering minorities with
strong opinions lest they be right. (Not that they are in this case :)) A
minority (particularly a minority of more than one) should be accomodated as
much as possible.

I tried to suggest that no global idiom would be more acceptable than a
global idiom that was unacceptable to at least three members of the WG, and
some other members of the community.

Pat's second RDF Model Theory document did have a solution to the meaning of
literals that was vague enough to satisfy everyone a bit (and nobody
completely?).

http://www.w3.org/TR/2002/WD-rdf-mt-20020214/

Key features were:

- literal were syntactically untidy
- no constraints were put on the mapping from literals to their values
- the range of the XL mapping was not necessarily a subset of the set IR
"Note that no particular relationship is assumed between IR and LV."

Since in that MT the entailment from

<jenny> <age> "10" .

to

<jenny> <age> _:x .

does not hold, it has actually remained fairly neutral on the truth or
falsity of the (A) questions. Moreover, the (D) question can't be asked
without a global idiom.


Thus to make a more concrete proposal for just having a local idiom:

+ use the Valentine's day MT
+ use the local idiom
+ for each datatype the value space is a subset of IR (this ensures that
bNodes can match datatyped values)

For someone who wishes to view this with tidy literal semantics, they are
free to restrict their view to interpretations in which XL is so restricted.

Is anyone interested in this?

Jeremy
Received on Monday, 29 July 2002 17:39:37 EDT

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