- From: Jos de Bruijn <debruijn@inf.unibz.it>
- Date: Wed, 24 Feb 2010 12:59:34 +0100
- To: Axel Polleres <axel.polleres@deri.org>
- CC: Sandro Hawke <sandro@w3.org>, Birte Glimm <birte.glimm@comlab.ox.ac.uk>, SPARQL Working Group <public-rdf-dawg@w3.org>
On 2010-02-24 12:53, Axel Polleres wrote: > Note in that context that, another issue is the following: > > RIF entailment is strictly speaking not only parametric to the > dialect (Core/BLD/strongly safe core ... I hope we can define a > unified entailmanet regime which catches all three) but also to the The definition of entailment is the same for all three, so I don't see why one would define different entailment regimes in the first place? Jos > combination semantics chosen, cf. > http://www.w3.org/TR/rif-rdf-owl/#Profiles_of_Imports, i.e. do we > want to define only a RIF/Simple-Entailment regime, or also: > > RIF/RDF RIF/RDFS RIF/D RIF/OWL RIF/OWL DL RIF/OWL Full > > (btw, the latter two have been renamed in the latest editor's draft > in RIF, , cf. > http://www.w3.org/2005/rules/wiki/SWC#Profiles_of_Imports, due to > comments form the OWL WG to RIF/OWL Direct RIF/OWL RDF-Based ) > > To start with, I think my original proposal works straightforwardly > for RIF/Simple, the others (particularly when we jump up to OWL) need > more thought, and probably checking back with Jos & Birte ;-) > > > Axel > > > P.S.: <chairhat-off>I note that for my main use case, which is > modeling different rule based approximations of fragments of the RDFS > and OWL semantics in RIF, RIF/Simple is probably > sufficient..</chairhat-off> > > > On 24 Feb 2010, at 11:38, Jos de Bruijn wrote: > >> >>>> On 2010-02-24 12:24, Axel Polleres wrote: >>>>> Below I forward some thought from jos on this with his >>>>> consent: >>>>> >>>>> @jos: can you ealborate what exactly you mean here: >>>>> >>>>>> 2- the RDF(S) semantics gives you more than just blank >>>>>> nodes. >>>>> >>>>> in how far is this a (potential) problem? >>>> >>>> I'm not saying this is a problem per se. You were simply not >>>> taking the RDF(S) semantics (i.e., axiomatic triples & >>>> semantics conditions) into account in the definition you >>>> proposed. >>> >>> yes, this is another issue. good point. >>> >>>> Of course one needs to be careful with the infinite axiomatic >>>> triples, especially when considering query answering and not >>>> just checking entailment. >>> >>> A common way to deal with this in a finite approximation way is >>> a) ignoring (specifically the infinite) axiomatic triples >>> alltogether b) take only those from the infinite axiomatic >>> triples (those about container membership properties) that appear >>> in the graph... I believe the latter is what we do in the current >>> RDF(S) entailment regime, yes Birte? >> >> b) seems to be the most reasonable way to go; but make sure to >> include at least one representative (for queries with blank >> nodes). Unnecessarily ignoring parts of the semantics (as in a) >> seems rather a bad idea. >> >> >> Cheers, Jos >> >>> >>> Axel >>> >>>> >>>> >>>> Jos >>>> >>>>> >>>>> Axel >>>>> >>>>> >>>>>> ============================================================================ >>>>>> >>>>>> On 2010-02-24 12:07, Axel Polleres wrote: >>>>>>> >>>>>>> On 24 Feb 2010, at 11:04, Jos de Bruijn wrote: >>>>>>>> On 2010-02-24 11:28, Axel Polleres wrote: >>>>>>>>> Hi Jos, >>>>>>>>> >>>>>>>>> Can you check this briefly and tell me whether I >>>>>>>>> don't oversimplify things here? >>>>>>>> >>>>>>>> I will have a more detailed look at it later on, but a >>>>>>>> few first comments: - you do not consider equality >>>>>>>> between data values, e.g. "1"^^int="1"^^decimal >>>>>>> >>>>>>> hmmm, I am at the moment, not sure how far this is a >>>>>>> problem, but I definitly should include this in the >>>>>>> issues! >>>>>>> >>>>>>> >>>>>>>> - I did not see how a minimal model for RIF-RDF >>>>>>>> combinations is defined, in particular I see no blank >>>>>>>> nodes or RDF(S) semantics >>>>>>> >>>>>>> ? Can't we just treat them as skolem constants? We are >>>>>>> just interested in query answering... >>>>>> >>>>>> 1- if you treat blank nodes as skolem constants you need to >>>>>> say so. 2- the RDF(S) semantics gives you more than just >>>>>> blank nodes. >>>>>> >>>>>>> if you agree, I forward your comments to SPARQL, ok? >>>>>> >>>>>> Sure. >>>>>> >>>>>> >>>>>> Jos >>>>> >>>>> >>>> >>>> -- Jos de Bruijn Web: http://www.debruijn.net/ Phone: +39 >>>> 0471 016224 Fax: +39 0471 016009 >>>> >>> >> >> -- Jos de Bruijn Web: http://www.debruijn.net/ Phone: +39 0471 >> 016224 Fax: +39 0471 016009 >> > -- Jos de Bruijn Web: http://www.debruijn.net/ Phone: +39 0471 016224 Fax: +39 0471 016009
Received on Wednesday, 24 February 2010 11:59:24 UTC