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Re: Entailment regimes open issues

From: Ivan Herman <ivan@w3.org>
Date: Mon, 08 Feb 2010 08:02:49 +0100
Message-ID: <4B6FB719.4000204@w3.org>
To: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>
I certainly agree with closing issues #28, #32, #40, #42.

I would propose to leave #43 for a while to see how the SD work evolves.
I predict that what you write below is true, but maybe discussions on SD
will allow for a finer granularity...

As far as I am concerned the biggest open issue I see in the entailment
document is the RIF part. The document still has to include an OWL Full
entailment which would also encompass, I presume, OWL RL; however I do
not see any problem with those, they seem to be a straightforward
extension to RDFS (but you are the specialist, you may know about extra

For RIF, there is a work that Sandro is doing that might be of importance:

http://www.w3.org/2005/rules/wiki/RIF_In_RDF (RIF In RDF)

essentially, RIF rules can be described in RDF triples. If that work is
concluded (hopefully the RIF group will have enough stamina to publish
this is a note) then things become way easier because we would not need
some sort of an extra import mechanism to include rules. If that problem
is out of the way than, I guess, the RIF semantics can be applied to
SPARQL, too... (again, the devil is in the details...)


On 2010-2-7 14:43 , Birte Glimm wrote:
> Hi all,
> for the entailment regimes we still have some open issues, but we
> discussed them in the entailment regimes teleconf on 13 Nov 2009 and I
> believe most can be closed.
> [ISSUE 28]: Entailment regimes vs. update?
> Section 9 of the entailment doc addresses this. The section says that
> systems that do use an entailment regime other than simple entailment
> can support update queries, but they don't have to. If they do support
> update queries, then the exact behavior is not covered by the spec and
> implementers can describe the system behavior in the system's
> documentation.
> I believe the issue can be closed.
> [ISSUE 34]: How do entailment regimes interaction with aggregates,
> grouping, and blank nodes?
> This was initially unclear because we were not sure how blank nodes
> would be handled. Since it s now clear that only blank nodes from the
> originally queried graph can be returned as answers (they are
> implicitly skolemized), the spec now clearly defines how counting,
> aggregates, and grouping works.
> I believe this issue can be closed.
> [ISSUE 40]: How can other entailment regimes plug in their semantics
> to SPARQL/Update?
> same as Issue 28 above
> [ISSUE 42]: TF-ENT What should happen for RDFS entailment in the face
> of inconsistencies?
> The current spec says that systems MAY raise an error and SHOULD do so
> if they encounter an inconsistency. Users cannot force a consistency
> check.
> [ISSUE 43]: should entailment-regimes be declared over the whole
> dataset or individual graphs?
> This issue relates mainly to service descriptions. At the moment SDs
> cannot describe endpoints that have some graphs with inferences and
> some graphs without. Such configurations will occur, but maybe it is
> just not part of SDs for now.
> If we agree that entailment regimes are per end-point for SPARQL 1.1,
> we can close this issue.
> Cheers,
> Birte


Ivan Herman, W3C Semantic Web Activity Lead
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Received on Monday, 8 February 2010 07:00:48 UTC

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