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Re: [TF-ENT] Agenda 24th Feb teleconf

From: Axel Polleres <axel.polleres@deri.org>
Date: Tue, 23 Feb 2010 10:31:30 +0000
Cc: Birte Glimm <birte.glimm@comlab.ox.ac.uk>, "SPARQL Working Group" <public-rdf-dawg@w3.org>
Message-Id: <64D60162-B655-43A7-9D20-7A01618421E2@deri.org>
To: Axel Polleres <axel.polleres@deri.org>
FWIW, here's what I had proposed to RIF (and the discussion in the folllowing thread)

short version...
http://lists.w3.org/Archives/Public/public-rif-wg/2010Jan/0015.html

lengthy version...
http://lists.w3.org/Archives/Public/public-rif-wg/2010Jan/0012.html


On 23 Feb 2010, at 10:25, Axel Polleres wrote:

>>  o Will/should RIF be marked as "at risk" depending on the RIF WG note
>>    about the RIF-to-RDF mapping? What is the status of the RIF to RDF
>>    mapping? Will there be something like rif:import?
> 
> I have made a proposal for rif:imports to the RIF list earlier, without much feedback so far, maybe also becasue I wasn't really pushing on it. One *awkward* workaround could be that we define rif:imports as part of the sparql work.
> 
> I personally see rif:imports as the easier way to go, compared to the RIF/RDF serialisation...
> opinions welcome.
> 
>>  o Will each rule set be an entailment regime, e.g., the SD says something
>>    like: myEndpoint sd:EntailmentRegime <http://example.org/myRules.rif>?
>>    Or is there a suitable RIF entailment relation (RIF+RDF semantics) and
>>    one specifies a rule set in a from clause or in the data set? Which RIF
>>    profiles does that cover? This might affect the condition on extensions
>>    to BGP matching that requires that
>>    SG E-entails (SG union P1(BGP1) union ... union Pn(BGPn))
> 
> if we have rif:imports than we don't need a separate entailment regime for each ruleset, IMO.
> 
>>  o How are blank nodes defined in RIF? Will skolemization/mapping to RIF
>>    local symbols work as for the other regimes?
> 
> Without having spent deep thought about it yet, I'd understand yes...
> 
> Basically, I would define RIF entailment by the rule closure.
> Note though, that this closure can be potentially infinite, so we have to make restrictions, which elements of the closure we consider (similar to what we have to do in OWL).
> 
> best,
> Axel 
> 
> On 21 Feb 2010, at 21:45, Birte Glimm wrote:
> 
>> Hi all,
>> here is a proposal for the agenda. If you have additional suggestions
>> or suggestions for amendments, let me know.
>> Birte
>> 
>>   *  Date of Call: Wednesday February 24, 2010
>>   * Time of Call: 18:00 UK, 13:00 (East US)
>>   * Dial-In #: +1.617.761.6200 (Cambridge, MA)
>>   * Dial-In #: +33.4.89.06.34.99 (Nice, France)
>>   * Dial-In #: +44.117.370.6152 (Bristol, UK)
>>   * Participant Access Code:
>>     Zakim will tell us when the ad hoc conference is set up
>>   * IRC Channel: irc.w3.org port 6665 channel #sparql-ent
>>     ([irc:irc.w3.org:6665/sparql-ent])
>>   * Duration: 60 minutes
>>   * Chair: Birte Glimm
>>   * Scribe: ?
>>   * Link to Agenda: http://www.w3.org/2009/sparql/wiki/Agenda-2010-02-24
>> 
>> * Admin
>>  o Do we need a scribe?
>> * General entailment regimes issues
>>  o Should we have a finite vocabulary from which bindings can be taken
>>    for all variables and not just the ones in subject position. This
>>    allows for defining the scoping graph as graph equivalent to the active
>>    graph even in the case of an inconsistency and would mean a modified C2
>>    condition.
>>    Current C2 in PWD:
>>    (C2) Each variable x that occurs in the subject position of a triple in
>>         BGP is such that sk(μ(x)) occurs in sk(SG).
>>    Proposed C2:
>>    (C2) For each variable x in V(BGP), sk(μ(x)) occurs in sk(SG) or in
>>         Vocab.
>>    Here vocal is defined as the reserved vocabulary for the entailment
>>    regime (e.g., the RDF vocabulary for RDF entailment) minus terms of the
>>    form rdf:_n with n in {1, 2, …}.
>> * RIF issues
>>  o Will/should RIF be marked as "at risk" depending on the RIF WG note
>>    about the RIF-to-RDF mapping? What is the status of the RIF to RDF
>>    mapping? Will there be something like rif:import?
>>  o Entailment regimes have to define which graphs the accept. Will the RIF
>>    entailment regime work with all RDF graphs? Different lists in RDF and
>>    RIF?
>>  o Will each rule set be an entailment regime, e.g., the SD says something
>>    like: myEndpoint sd:EntailmentRegime <http://example.org/myRules.rif>?
>>    Or is there a suitable RIF entailment relation (RIF+RDF semantics) and
>>    one specifies a rule set in a from clause or in the data set? Which RIF
>>    profiles does that cover? This might affect the condition on extensions
>>    to BGP matching that requires that
>>    SG E-entails (SG union P1(BGP1) union ... union Pn(BGPn))
>>  o How are blank nodes defined in RIF? Will skolemization/mapping to RIF
>>    local symbols work as for the other regimes?
>>  o Not all RIF dialects are based on a model-theory (e.g., RIF PRD), so
>>    they do not come with an entailment relation, but have a procedural
>>    semantics. Can we still use the procedural semantics to define
>>    something like an entailment regime?
>>  o Which RIF profiles should be included? Only RIF Core? Does RIF Core
>>    coincide with OWL RDF-Based or Direct Semantics? How many profiles are
>>    there?
>>  o What effects do the non-monotonic features of some RIF dialects have?
>>    E.g., RIF PRD and (anticipated) RIF dialects with default negation.
>>    How does that interact with SPARQL's non-monotonic features?
>>    This probably affects issue-43: Should entailment-regimes be declared
>>    over the whole dataset or individual graphs?
>>  o RIF production rules: it is no even clear how conjunctive queries work.
>>  o What is our timeline for RIF?
>> 
>> --
>> Dr. Birte Glimm, Room 306
>> Computing Laboratory
>> Parks Road
>> Oxford
>> OX1 3QD
>> United Kingdom
>> +44 (0)1865 283529
>> 
>> 
> 
Received on Tuesday, 23 February 2010 10:32:05 GMT

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