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Re: Thinking out lout about some strange SPARQL entailment test cases...

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Fri, 27 Aug 2010 23:32:38 +0100
Message-ID: <AANLkTimv0jAivxjHUyWYv3CLCmKvYY=zkRKsWo=5mu4W@mail.gmail.com>
To: "Polleres, Axel" <axel.polleres@deri.org>
Cc: public-rdf-dawg@w3.org
On 27 August 2010 20:13, Polleres, Axel <axel.polleres@deri.org> wrote:
> Yes, the second one was meant as D-entailment test case, and I expected both not to return any result.

Because it is not well-formed RDF or because you think it is not entailed?
Birte

> Axel
>
> ----- Original Message -----
> From: b.glimm@googlemail.com <b.glimm@googlemail.com>
> To: Polleres, Axel
> Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
> Sent: Fri Aug 27 20:11:39 2010
> Subject: Re: Thinking out lout about some strange SPARQL entailment test cases...
>
> Sorry, I didn't comment on the second test case
>
>> Similarly:
>>
>>  G:
>>   :s :p 1
>>
>>  Q:
>>  SELECT ?L
>>  WHERE { ?L a xsd:integer }
>
> I think that would need datatype awareness and RDFS does not support
> the XSD schema datatypes (you would need D-Entailment or higher). Even
> if we have
> :s :p "1"^^xsd:integer.
> a system unaware of xsd datatypes might read that triples, but it will
> not necessarily infer
> "1"^^xsd:integer a xsd:integer .
> or even
> "1"^^xsd:integer a xsd:short .
> which is also true I guess. At least for OWL reasoners what counts
> internally is the denoted data value and "1"xsd:short and
> "1"xsd:integer is the same data vale with different lexical forms. Now
> for OWL Direct Semantics that BGP is not legal, so your only hope
> would be OWL with RDF-Based Semantics or some D-Entailment
> implementation.
>
> Now, even with XSD awareness and not counting it as illegal RDF, the
> answers would not be infinite because you only consider the data
> values in the graph.
>
> Birte
>
>>
>> Obviously, those will not give an answer, but some people might expect those to return surrogate blank nodes... a colleague of mine just came to me with that (in a different context), and I thought I might share it.
>>
>> Axel
>
>
>
> --
> Dr. Birte Glimm, Room 309
> Computing Laboratory
> Parks Road
> Oxford
> OX1 3QD
> United Kingdom
> +44 (0)1865 283520
>



-- 
Dr. Birte Glimm, Room 309
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283520
Received on Friday, 27 August 2010 22:33:16 GMT

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