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Re: xsd:float and xsd:decimal

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Thu, 28 Nov 2002 15:31:51 +0000 (GMT)
To: Brian McBride <bwm@hplb.hpl.hp.com>
cc: Patrick Stickler <patrick.stickler@nokia.com>, ext Jeremy Carroll <jjc@hpl.hp.com>, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.44.0211281525450.12073-100000@mail.ilrt.bris.ac.uk>

On Thu, 28 Nov 2002, Brian McBride wrote:

> >I'm fine with this as long as it is clear (somewhere) that
> >datatype entailments involving equality of values between
> >different datatypes are based on the definitions of the
> >datatypes themselves, and if the relationships between
> >the datatypes are not part of the formal definitions of
> >the datatypes, then the entailments cannot be determined.
> >
> >I.e. we need to be clear about the basis for the entailments
> >and not work solely on the basis of human intuition.
>
> Patrick,
>
> May I test my understanding of what you mean here.  I offer two datatype
> definitions and an entailment.

Patrick's concerns come down to this, I think: what _machinery_ is
mandated for determining a RDF-D entailment? Do we say, we expect
reasoners to only copy when given subClassOf relationships between
datatypes?

That is a limited form of reasoning and would not catch other
entailments such as the one you give in your example.

I think the definition I proposed for the DT entailment test cases, that

	"supporting datatypes X, Y, Z, ..."

	means

	"For two DT literals, each with a type from {X, Y, Z, ...},
	you can determine whether they denote the same value"

	(determining the value itself is not required)

is a reasonable one. In fact, a service that could broker such
decision-making machinery given a pair of datatypes is close to an
archetypal example of a "semantic web service". At the moment, we don't
have much machinery (additional layers on RDF) to be able to do this
declaratively (the DT knowledge needs to be encoded in programs) but
I was under the impression that this is something that one would expect
to find in a "semantic web layer cake".


-- 
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/
stty intr ^m
Received on Thursday, 28 November 2002 10:32:53 EST

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