- From: Polleres, Axel <axel.polleres@deri.org>
- Date: Fri, 27 Aug 2010 20:13:21 +0100
- To: <birte.glimm@comlab.ox.ac.uk>
- Cc: <public-rdf-dawg@w3.org>
Yes, the second one was meant as D-entailment test case, and I expected both not to return any result. 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
Received on Friday, 27 August 2010 19:13:58 UTC