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Re: [Fwd: Comments on SPARQL] (entailment, soundness, completeness)

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 09 Sep 2005 19:19:20 -0400
Message-ID: <43221878.1050209@research.bell-labs.com>
To: public-rdf-dawg-comments@w3.org


>The WG as a whole hasn't expressed a preference directly, but in
>drafting the definitions and considering simple test cases, the
>details of subgraph seemed to work out and the details of entailment
>seemed not to. For example, here's part of one message from 09 Jun 2005
>
>
>[[[
>The difference is observable from an approved*** test
>  http://www.w3.org/2001/sw/DataAccess/tests/#dawg-triple-pattern-001
>
>input:
> :x :p :v1 .
> :x :p :v2 .
>
>query:
>  SELECT *
>WHERE { :x ?p ?q . }
>
>By the simple-entailment definition, there are solutions that bind
>?p to _:foo, but there are no such results in the test results.
>I suppose it's possible that the spec could prune the results
>down to the ones in the test suite some other way, but I can't
>think of any other straightforward way just now.
>]]]
> -- Re: Restructure definition of Basic Graph Pattern and pattern match (sec 2.4)
>http://lists.w3.org/Archives/Public/public-rdf-dawg/2005AprJun/0359
>
>  
>

Hmm.  I don't think so.  Binding ?p to _:foo doesn't result in an RDF 
graph, as far as I know, and thus can't participate in an entailment 
relationship.

Peter F. Patel-Schneider
Bell Labs Research
Received on Friday, 9 September 2005 23:15:36 GMT

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