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

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Wed, 20 Nov 2002 16:04:58 +0000
Message-Id: <5.1.0.14.0.20021120154241.02f849e8@0-mail-1.hpl.hp.com>
To: Jan Grant <Jan.Grant@bristol.ac.uk>, pat hayes <phayes@ai.uwf.edu>, Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: RDFCore Working Group <w3c-rdfcore-wg@w3.org>

At 14:49 20/11/2002 +0000, Jan Grant wrote:

[...]

> >
> > We know that:
> >
> >   <a> <b> "foo"@@en#<datatype> .
> >   <c> <d> "foo"@@fr#<datatype> .
> >
> > entails
> >
> >   <a> <b> _:l .
> >   <c> <d> _:l .
> >
> > for all datatypes except rdf:XMLLiteral.
>
>It does? Doh.

I think so, but don't take my word for it.  Jeremy?

>I still think that's broken; but I'll fix the test case.
>Basically these cases outline the various issues - I'll correct them as
>appropriate.

Nah - see below - you got it right unless we know that datatype is not 
rdf:XMLLiteral.  We know its not called that, but unless we make a unique 
name assumption, we don't know that its not another name for the same thing.

[...]


>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

[...]


>I'm happy to revise this if you think it's necessary.


Lets get confirmation first

Brian
Received on Wednesday, 20 November 2002 11:03:33 EST

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