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Re: [TF-ENT] A few comments on RDFS Entailment section

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Tue, 6 Oct 2009 14:09:24 +0100
Message-ID: <492f2b0b0910060609n36004c06qe9f8a71a4af61eb2@mail.gmail.com>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
Cc: SPARQL WG <public-rdf-dawg@w3.org>
[snip]


>> > Under simple entailment matching there is one because "P(BGP) is a
>> subgraph of G" and not an entailment relationship, and ?x=_:x.  (DAWG did
>> try for an entailment relationship but the cardinality issues were a
>> problem.)
>> >
>> Yes, we need a similar condition for entailment regimes but not based
>> on pure subgraph matching.
>>
>> For now we have this as an open problem and how queries over different
>> named graphs should behave (do we take entailments into account that
>> depend on triples from different named graphs). I'll try and add notes
>> for these two issues in the ent. regimes doc.

I have added notes for this issue and for the named graphs issue that
Steve mentioned to the doc, so we can't forget them. I hope I have
some time during the flight/at the airport to think about how we can
best handle this.

Birte

>> Just to see whether I get simple entailment right. If you have
>> :s :p :o
>> and query with BGP
>> ?x :p :o
>> you would only get ?x=:s and not ?x=_:x for some blank node _:x,
>> right? I mean you have the RDF simple entailment rules se1 and se2
>> (http://www.w3.org/TR/rdf-mt/#simpleRules), which could be used to add
>> _:x :p :o with se2, but you do not use that, right? For simple
>> entailment one just has to check sub-graphs of the queried graph.
>
> That's my reading.  That's what the "sub-graph" brings.
>
>        Andy
>
>>
>> Birte
>>
>>
>>
>> >        Andy
>> >
>> >
>>
>>
>>
>> --
>> Dr. Birte Glimm, Room 306
>> Computing Laboratory
>> Parks Road
>> Oxford
>> OX1 3QD
>> United Kingdom
>> +44 (0)1865 283529
>



-- 
Dr. Birte Glimm, Room 306
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283529
Received on Tuesday, 6 October 2009 13:10:00 GMT

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