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Re: Action needed: subClassOf on datatypes

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Tue, 2 Sep 2003 11:57:18 +0100 (BST)
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: pat hayes <phayes@ihmc.us>, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Message-ID: <Pine.GSO.4.44.0309021152160.22152-100000@mail.ilrt.bris.ac.uk>

On Tue, 2 Sep 2003, Jeremy Carroll wrote:

>
>
> Summary:
> Prefer c++
> modify  the test case to say that the case is D-consistent with the
> empty graph, not that it is D-entailed by it;
> add D-inconsistent test using a different rdfs:subClassOf triple between
> xsd datatypes.
>
>
>
>
> pat hayes wrote:
>
>
> > (a) modify the test case doc by deleting the test case;
>
> Not particularly OK, well unless the semantics doc discusses
> rdfs:subClassOf in datatyping clearly. i.e. this should not be left as an
> exercise for the reader.
>
> > (b) modify the test case to say that this only follows under the
> > strengthened extensional semantic conditions on rdfs:subClassOf
> > described in section 4.1 of the semantics document;
>
> not good
>
> > (c) modify  the test case to say that the case is D-consistent with the
> > empty graph, not that it is D-entailed by it;
>
> OK
> Also add a test case showing that
> xsd:string rdfs:subClassOf xsd:integer .
> is inconsistent.
>
> > (d) modify the semantics of D-interpretations to insist that datatype
> > class subsetting *is* treated extensionally, so that the rule rdfD4 is
> > valid and the test case is OK. This can be done by adding the following
> > semantic condition on D-interpretations:
>
> Prefer (c) to this.
> (Another option is to explicitly list rdfs:subClassOf relationships between
> xsd datatypes as true by fiat).

This last option seemed the "obvious" one to me: that a datatype
definition might well include subClassOf "axiomatic triples".

The test case document currently doesn't have explicit
"consistent/inconsistent" test cases; these have usually been encoded
using entailment or non-entailment of false graphs.

So the new test cases would be that:

1.
[[
	xsd:integer rdfs:subClassOf xsd:decimal .
]] DOES NOT rdfs+D(xsd:integer, xsd:decimal)-entail
[[ FALSE ]] (the "false" graph)

2.
[[
	xsd:integer rdfs:subClassOf xsd:string .
]] rdfs+D(xsd:integer, xsd:string)-entails
[[ FALSE ]]


... is that ok?








-- 
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/
It's a sad fact that the word "semantics" seems to have lost all meaning.
Received on Tuesday, 2 September 2003 09:21:09 EDT

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