- From: Axel Polleres <axel.polleres@deri.org>
- Date: Sat, 27 Sep 2008 17:16:34 -0400
- To: Axel Polleres <axel.polleres@deri.org>
- CC: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Axel Polleres wrote: > Ooops, forget it, the examples was nonsense... seems that the jetlag > kicks in. but I am still not entirely convinced that only negative > guards are the problem. > > axel sorry, sorry, rethought it. indeed only the negative guards are the preds defined in terms of failure of another predicate, so indeed they are the only problematic ... > Axel Polleres wrote: >> Please note that Jos pathological use case >> >> http://www.w3.org/2005/rules/wiki/Disjunctive_Information >> >> can very similarly be modeled with comparison operators, which doesn't >> only put negative guards, but also our "convenient" >> less-than-or-equal, greater-than-or-equal predicates at risk: >> >> >> Document( >> Prefix(ex http://example.com/example#) >> Prefix(pred http://www.w3.org/2007/rif-builtin-predicate#) >> >> Group( >> ex:p(ex:a) >> Forall ?x (1=2 :- And (ex:p(?x) pred:less-than(?x 5) >> pred:greater-than(?x 0) ) ) >> ) >> >> entails: >> >> Or ( pred:greater-than-or-equal(ex:a 5) >> pred:less-than-or-equal(ex:a 0) ) >> >> >> best, >> Axel >> >> > > -- Dr. Axel Polleres, Digital Enterprise Research Institute (DERI) email: axel.polleres@deri.org url: http://www.polleres.net/ Everything is possible: rdfs:subClassOf rdfs:subPropertyOf rdfs:Resource. rdfs:subClassOf rdfs:subPropertyOf rdfs:subPropertyOf. rdf:type rdfs:subPropertyOf rdfs:subClassOf. rdfs:subClassOf rdf:type owl:SymmetricProperty.
Received on Saturday, 27 September 2008 21:17:18 UTC