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Re: [TF-Ent] RIF Core Entailment section

From: Chimezie Ogbuji <ogbujic@ccf.org>
Date: Thu, 11 Mar 2010 12:30:57 -0500
To: "Birte Glimm" <birte.glimm@comlab.ox.ac.uk>, "Ivan Herman" <ivan@w3.org>
cc: "SPARQL Working Group WG" <public-rdf-dawg@w3.org>, "Axel Polleres" <axel.polleres@deri.org>, "Sandro Hawke" <sandro@w3.org>
Message-ID: <C7BE9301.104AC%ogbujic@ccf.org>
Comments below

On 3/10/10 9:35 AM, "Birte Glimm" <birte.glimm@comlab.ox.ac.uk> wrote:
> Yes, that's what I mean. As I understand it SG or sk(SG) is the graph
> you get from the triples and it knows nothing about the rule set. We
> would have to specify a vocabulary that is the union of the vocabulary
> of SG/sk(SG) and the vocabulary of the import closure of the
> referenced rule sets. That's not difficult to do, we should just add
> it.

Do we even need this condition for RIF Simple entailment? The vocabulary of
the generalized RDF graphs entailed by the combination (strongly, safe RIF
Core document,sk(SG)) 'include' the vocabulary of SG and the corresponding
RDF names in the RIF document (this also includes its import closure).  Is
there an example that demonstrates needing anything more than requiring that
the RDF triples sk(P(BGP)) are ground and RIF-Simple entailed by the
combination?

I have updated the Simple RIF Core entailment regime with a paragraph that
briefly discusses this.  Going back to your example below

.. if we have SG:
ex:a a ex:b .
rif-rdf:usesRuleset ex:rules.rif .

with ex:rules.rif:
ex:b(x) -> ex:c(x)

and query:

SELECT ?x WHERE { ?x a ex:c }

Then I (too) would expect to get ?x/ex:a

In this case sk(P(BGP)) is the same as P(BGP):

ex:a a ex:c

And the entailed, generalized graph EG would be (a proper superset of SG):

ex:a a ex:b .
ex:a a ex:c

In which case P(BGP) is a subgraph of EG.  So, there is no need to
explicitly restrict the bound names.


-- Chime


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Received on Thursday, 11 March 2010 17:51:32 GMT

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