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Re: Datatype test cases: important ones (please have a look)

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Wed, 20 Nov 2002 14:33:55 +0000
Message-Id: <>
To: Jan Grant <Jan.Grant@bristol.ac.uk>, RDFCore Working Group <w3c-rdfcore-wg@w3.org>

Well done Jan.  Good to see this moving forward.

test1: rdf is not well formed xml.
   xml:lang="fr">10</eg:bar> should be xml:lang="fr">10</eg:baz>


this is not what I expected

[[# Language doesn't affect the semantic equivalence of some datatypes,
# when doing a DT-entailment. However, it represents a difference
# when doing DT-unaware entailment.]]

We know that:

  <a> <b> "foo"@@en#<datatype> .
  <c> <d> "foo"@@fr#<datatype> .


  <a> <b> _:l .
  <c> <d> _:l .

for all datatypes except rdf:XMLLiteral.

It is not necessary to be datatype aware to figure out this entailment.  I 
suppose there is always the possibility that someone has given a different 
URI for rdf:XMLLiteral.  Hmm, that's a shame.  Its only true if we know 
datatype is distinct from rdf:XMLLiteral.

This feels a bit shady, but I guess you are right.


The representation of a semantic error is that the erroneous triple entails 
the empty graph.  I'm not sure this captures it. Any graph entail the empty 
graph, right?  I remember something in the model theory about a bad literal 
denoting something, just not a datatype.  If I remember rightly we would 
have a negative entailment:

<a> <b> "foo"^^xsd:integer

does not entail

<a> <b> _:v .
_:v rdf:type _:c .
_:c rdf:type rdfs:Datatype .

and it does if we replace "foo" with "10".


The comment:

[[Language doesn't affect the semantic equivalence of some datatypes,
	when doing a DT-entailment]]

Where some = all except rdf:XMLLiteral.


I'd rather we didn't say this at all.  This is a statement about the 
features of xml schema datatypes, not about rdf and datatyping.

If we do decide to keep it (grrrr) then I'd suggest formulating it 
differently.  The way this is put suggests that

  <a> <b> "10"^^xsd:integer .

entails all other datatype representations of the same value.  Suggest instead:

  <a> <b> "10"^^xsd:integer .
  <c> <d> "1E1"^^xsd:decimal .


  <a> <b> _:v .
  <c> <d> _:v .

which is more constrained.

Received on Wednesday, 20 November 2002 09:32:32 UTC

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