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Re: Entailment Doc ready for review

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Thu, 16 Sep 2010 11:55:25 +0100
Message-ID: <AANLkTi=minKnqcOwGy64tDuQu-goN4Ugdgb4cKkMgcmu@mail.gmail.com>
To: Olivier Corby <olivier.corby@sophia.inria.fr>
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
On 16 September 2010 07:01, Olivier Corby <olivier.corby@sophia.inria.fr> wrote:
> Before writing my review on entailment, I have a question on this point:
> section 2.4 Boolean Queries (Informative)
> The two conditions C1 and C2 also have an effect on the answers to Boolean
> queries. For Boolean queries that contain variables, e.g.,
> ASK { ?x a rdf:Property }
> The query answer is yes (true) if there is at least one solution mapping
> (i.e., a solution that satisfies also conditions C1 and C2) and it is no
> (false) otherwise. For example, if the queried graph is the empty graph, the
> query has no solution since even if a pattern instance mapping yields an
> axiomatic triple, condition C2 cannot be satisfied.
> My question is why condition C2 cannot be satisfied ?

Good question indeed. The example is wrong. I think I did not take
into account that not only the rdf:_1, rdf:_2, ... replaced for ?x
lead to an entailed triples, but we also have
rdf:type rdf:type rdf:Property .

C2 only prohibits the infinitely many rdf:_1, rdf:_2, ... , but not
rdf:type for example.

Maybe we just remove that example?


> Thanx,
> Olivier

Dr. Birte Glimm, Room 309
Computing Laboratory
Parks Road
United Kingdom
+44 (0)1865 283520
Received on Thursday, 16 September 2010 10:55:53 UTC

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