- From: Axel Polleres <axel.polleres@deri.org>
- Date: Sat, 28 Aug 2010 10:08:16 +0100
- To: "Birte Glimm" <birte.glimm@comlab.ox.ac.uk>
- Cc: <public-rdf-dawg@w3.org>
On 27 Aug 2010, at 23:32, Birte Glimm wrote: > On 27 August 2010 20:13, Polleres, Axel <axel.polleres@deri.org> wrote: > > Yes, the second one was meant as D-entailment test case, and I expected both not to return any result. > > Because it is not well-formed RDF or because you think it is not entailed? What would be entailed was _:SURROGATE_BNODE_FOR_1 a xsd:integer cf. entailment rule rdfD1 (Section 7.4) in the informative entailment rules of rdf-mt [1]. but at the moment we don't bother about "surrogate" bnodes for literals, but only return terms appearing in the orignal graph. (similarly for the RDFS example) I only meant those test cases for making that clear to users/implementers: That is, if I implement RDFS/D entailment by implementing the informative entailment rules, I get results which are not mandated by our current definitions of RDFS/D entailment in SPARQL. Hope that the intention is clearer now, Axel 1. http://www.w3.org/TR/rdf-mt/ > Birte > > > Axel > > > > ----- Original Message ----- > > From: b.glimm@googlemail.com <b.glimm@googlemail.com> > > To: Polleres, Axel > > Cc: SPARQL Working Group <public-rdf-dawg@w3.org> > > Sent: Fri Aug 27 20:11:39 2010 > > Subject: Re: Thinking out lout about some strange SPARQL entailment test cases... > > > > Sorry, I didn't comment on the second test case > > > >> Similarly: > >> > >> G: > >> :s :p 1 > >> > >> Q: > >> SELECT ?L > >> WHERE { ?L a xsd:integer } > > > > I think that would need datatype awareness and RDFS does not support > > the XSD schema datatypes (you would need D-Entailment or higher). Even > > if we have > > :s :p "1"^^xsd:integer. > > a system unaware of xsd datatypes might read that triples, but it will > > not necessarily infer > > "1"^^xsd:integer a xsd:integer . > > or even > > "1"^^xsd:integer a xsd:short . > > which is also true I guess. At least for OWL reasoners what counts > > internally is the denoted data value and "1"xsd:short and > > "1"xsd:integer is the same data vale with different lexical forms. Now > > for OWL Direct Semantics that BGP is not legal, so your only hope > > would be OWL with RDF-Based Semantics or some D-Entailment > > implementation. > > > > Now, even with XSD awareness and not counting it as illegal RDF, the > > answers would not be infinite because you only consider the data > > values in the graph. > > > > Birte > > > >> > >> Obviously, those will not give an answer, but some people might expect those to return surrogate blank nodes... a colleague of mine just came to me with that (in a different context), and I thought I might share it. > >> > >> Axel > > > > > > > > -- > > Dr. Birte Glimm, Room 309 > > Computing Laboratory > > Parks Road > > Oxford > > OX1 3QD > > United Kingdom > > +44 (0)1865 283520 > > > > > > -- > Dr. Birte Glimm, Room 309 > Computing Laboratory > Parks Road > Oxford > OX1 3QD > United Kingdom > +44 (0)1865 283520 >
Received on Saturday, 28 August 2010 09:08:55 UTC