- From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
- Date: Wed, 24 Feb 2010 21:49:35 +0000
- To: SPARQL Working Group <public-rdf-dawg@w3.org>
Hi all, Below a short summary for the points we discussed in today's teleconf. * General entailment regimes issues There was no clear consensus whether the modified C2 should be used. Topic is discussed further by mail (see my separate follow-up email on this). * 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? Not necessary. RIF hopefully is a REC within ~2 month. We'll see how far we are when we go to last call. o Will there be something like rif:import? Most likely SPARQL will define a special keyword for this. E.g., a graph containing a triple [] sparql:useRuleSet URI_to_rule_set will have special meaning for a system that uses RIF entailment and the system will treat this similar to an owl imports directive and attempt to load rules from the document at URI_to_rule_set. 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? For now we assume yes. 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)) Not necessary if there is some form of import, e.g., as the one described above. o How are blank nodes defined in RIF? Will skolemization/mapping to RIF local symbols work as for the other regimes? That seems to be no problem. Then we discussed how we can guarantee finiteness in different RIF dialects. The strongly safe part of RIF Core (strongly safe is informative in the RIF spec) seems to be easy (one can build a finite Herbrand model, partial closure). The other dialects are not very straightforward. Sandro suggested dropping the condition of finiteness and sees no formal problems since that will not invalidate existing implementations. Other are more worried about changing the SPARQL 1.0 conditions. So far, we'll continue the discussion about how to achieve finite answers in next week's teleconf. Birte -- Dr. Birte Glimm, Room 306 Computing Laboratory Parks Road Oxford OX1 3QD United Kingdom +44 (0)1865 283529 -- Dr. Birte Glimm, Room 306 Computing Laboratory Parks Road Oxford OX1 3QD United Kingdom +44 (0)1865 283529
Received on Wednesday, 24 February 2010 21:50:07 UTC