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Re: do bad datatype literals denote [was Re: Datatype test cases ...]

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Wed, 20 Nov 2002 16:23:26 +0000 (GMT)
To: Brian McBride <bwm@hplb.hpl.hp.com>
cc: pat hayes <phayes@ai.uwf.edu>, Jeremy Carroll <jjc@hplb.hpl.hp.com>, RDFCore Working Group <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.44.0211201616100.12073-100000@mail.ilrt.bris.ac.uk>

On Wed, 20 Nov 2002, Brian McBride wrote:

> [attribution lost - the other person is me]
> >NO. This is related to what Pat was complaining about. Basically, a
> >"Positive entailment test" with premise document P and consequent
> >document C passes if:
> >
> >         - P has an interpretation (ie, contains no semantic errors
> >           wrt the constraints imposed by the interpretation rules used
> >           for the test case) AND
> >         - P entails C.
> >
> >A "negative entailment test" passes if:
> >
> >         - P has no valid interpretations (contains a semantic error) OR
> >         - P is ok but does not entail C.
> OK, so because its a neg entailment of the empty graph, then by this rule,
> there can be no valid interpretations.  I thought the model theory had bad
> datatype lex forms denoting something though, in which case there is an
> interpretation.  Right, from 3.4 of the MT:
> [[For any typed literal "sss"^^ddd in G, if I(ddd) is in D and 'sss' is not
> a valid lexical form for I(ddd) then IL("sss"^^ddd) is not in LV]]
> and
> [[(this) condition requires than an 'ill-formed' typed literal, i.e. one
> where the literal string is not in the lexical space of the datatype, not
> denote any literal value. Intuitively, such a name does not denote any
> value, but in order to avoid the semantic complexities which arise from
> empty names, we requires such a typed literal to denote an 'arbitrary' value.]]
> Thus there are interpretations of the graph
>    http://www.w3.org/2000/10/rdf-tests/rdfcore/datatypes/test002.nt
> and the test does not work

Yech. The words that the current test case WD uses are _extremely_

A premise document that contains a semantic error with respect to any
constraints imposed by the entailment rules selected will cause this
[positive entailment] test to fail.

and in particular, it's the case of duff lexical forms for datatyped
literals that I wanted to cover with this. In other words, if a graph
contains datatyped literals that need to be given "arbitrary"
denotations, that's (one kind of) the "semantic error" I was alluding

This clearly needs putting in better terms. If the entailement tests can
be utilised for this purpose in their current form but with better
wordsmithing, that'd be good - but clearly some better words are
required, because the definition is currently clearly lacking!


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/
Work #90: As many pseudo-intellectual sycophants as necessary to make one
inarticulate scotsman think he's a genius in command of The Profound.
Received on Wednesday, 20 November 2002 11:24:26 UTC

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