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Re: Re: LC Comment: Restriction on Solutions for RDF-Based Entailment Regime

From: Michael Schneider <schneid@fzi.de>
Date: Fri, 18 Nov 2011 19:22:53 +0100
Message-ID: <4EC6A27D.5020907@fzi.de>
To: <public-rdf-dawg-comments@w3.org>
CC: <birte.glimm@uni-ulm.de>
Dear SPARQL Working Group,

as far as I can see, the new example works well and is indeed simpler 
than the one that I have proposed.

I acknowledge that my comment has been answered.

Best regards,

Am 20:59, schrieb Birte Glimm:
> Michael,
> Thank you for your comment and the clarification about the editorial
> comment regarding infiniteness due to datatype reasoning under OWL's
> RDF-Based Semantics.
> The current editor's draft no longer contains the editorial note and
> includes an even simpler example that already illustrates the point.
> The current editor's draft is available at:
> http://www.w3.org/2009/sparql/docs/entailment/xmlspec.xml
> We would be grateful if you would acknowledge that your comment has
> been answered by sending a reply to this mailing list.
> Birte, on behalf of the SPARQL-WG
> On 30 July 2011 19:36, Michael Schneider<schneid@fzi.de>  wrote:
>> Dear all!
>> The SPARQL 1.1 Entailment Regimes LCWD, Section 5.2 "Restriction on
>> Solutions" in the Chapter defining the OWL 2 RDF-Based Entailment Regime,
>> contains an example query consisting of several complex class expressions
>> and an Editorial Note, which states
>>     It could be the case that this example only applies to the
>>     OWL 2 Direct Semantics and that for the RDF-Based Semantics
>>     one would have to introduce axioms that force a domain
>>     element to exist for each extension of the class expressions
>>     ...
>> This is correct.
>> There is, however, an alternative kind of query, which would be close in the
>> spirit of the current query, but without suffering from the problem of the
>> RDF-Based Semantics that one needs the existence of individuals representing
>> class or property extensions:
>> One can use a query based on a /negative data property assertions/, for
>> example in the following form:
>>     SELECT ?x WHERE {
>>         _:z rdf:type owl:NegativePropertyAssertion ;
>>         _:z owl:sourceIndividual ex:peter ;
>>         _:z owl:assertionProperty ex:dp ;
>>         _:z owl:targetValue ?x .
>>     }
>> The expected possible results of this query would, as for the current query,
>> be all literals L to which ex:peter does /not/ have a ex:dp-relationship,
>> e.g. L := "6"^^xsd:integer and so on, so the result set would be infinite,
>> if not restricted.
>> There is a specific RDF-based semantic condition that ensures the existence
>> of such a "_:z" that combines the triples in the multi-triple representation
>> of negative property assertions:
>> <http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/#item-semcond-negassert-data-bw>
>> Best regards,
>> Michael

Dipl.-Inform. Michael Schneider
Research Scientist, Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: michael.schneider@fzi.de
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FZI Forschungszentrum Informatik an der Universität Karlsruhe
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Vorstand: Dipl. Wi.-Ing. Michael Flor, Prof. Dr. rer. nat. Ralf Reussner,
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Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
Received on Friday, 18 November 2011 18:23:34 UTC

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