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Re: putting entailment into SPARQL

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 20 Dec 2005 08:48:12 -0600
Message-Id: <p06230900bfcdc93d7e9a@[192.168.2.2]>
To: Sergio Tessaris <tessaris@inf.unibz.it>
Cc: Eric Prud'hommeaux <eric@w3.org>, "Seaborne, Andy" <andy.seaborne@hp.com>, RDF Data Access Working Group <public-rdf-dawg@w3.org>

>On 13 Dec 2005, at 23:27, Pat Hayes wrote:
>
>>Pattern Solution.
>>A variable substitution is a substitution function on a subset of V 
>>to RDF-T. A pattern solution on the pattern V to the dataset G is a 
>>variable substitution whose domain includes all the variables in V, 
>>whose range is a subset of the set of RDF terms occurring in G, and 
>>which matches the dataset DS.
>
>Pat, by restricting the domain in this way you rule out RDF(S) 
>entailment, since there are terms which should be in any RDF(S) 
>graph, even if not explicitly mentioned (e.g. rdf:type or 
>rdf:Property).

We  should discuss this. I intended to restrict in this way for all 
entailments. That is, I do not think that tautological queries should 
succeed against an empty graph, even when they are entailed. The 
point of querying is not primarily to test entailment, but to find 
out what is in the actual graph.

>My understanding is that this restriction should be enforced for bnodes only.

IMO that would be too narrow. But if you think the global restriction 
is too tight, can you show some examples?

Pat

>
>--sergio


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Received on Tuesday, 20 December 2005 14:48:42 GMT

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