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Re: Entailment regimes open issues

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Mon, 8 Feb 2010 12:31:12 +0000
Message-ID: <492f2b0b1002080431q1962e550uda4b56c2516feef7@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
> 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...

Fine with me.

> 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
> problems...).
> 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...)

One more problem for the RIF part is that I've always said that we
need an editor for RIF and that won't be me. I have not even read the
RIF spec (skimmed over parts that touch OWL) and I don't have the time
to first understand RIF and which parts of RIF are suitable to
integrate with SPARQL and how that can be done properly. We would
really need somebody with RIF background to put in the time to write


> Ivan
> 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
> Home: http://www.w3.org/People/Ivan/
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Dr. Birte Glimm, Room 306
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Received on Monday, 8 February 2010 12:31:46 UTC

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