- From: Michael Schneider <schneid@fzi.de>
- Date: Sat, 30 Jul 2011 19:36:21 +0200
- To: <public-rdf-dawg-comments@w3.org>
Dear all! The SPARQL 1.1 Entailment Regimes LCWD, Section 5.2 "Restriction on Solutions" in the Chapter defining the OWL 2 RDF-Based Entailment Regime, contains an example query consisting of several complex class expressions and an Editorial Note, which states It could be the case that this example only applies to the OWL 2 Direct Semantics and that for the RDF-Based Semantics one would have to introduce axioms that force a domain element to exist for each extension of the class expressions ... This is correct. There is, however, an alternative kind of query, which would be close in the spirit of the current query, but without suffering from the problem of the RDF-Based Semantics that one needs the existence of individuals representing class or property extensions: One can use a query based on a /negative data property assertions/, for example in the following form: SELECT ?x WHERE { _:z rdf:type owl:NegativePropertyAssertion ; _:z owl:sourceIndividual ex:peter ; _:z owl:assertionProperty ex:dp ; _:z owl:targetValue ?x . } The expected possible results of this query would, as for the current query, be all literals L to which ex:peter does /not/ have a ex:dp-relationship, e.g. L := "6"^^xsd:integer and so on, so the result set would be infinite, if not restricted. There is a specific RDF-based semantic condition that ensures the existence of such a "_:z" that combines the triples in the multi-triple representation of negative property assertions: <http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/#item-semcond-negassert-data-bw> Best regards, Michael -- Dipl.-Inform. Michael Schneider Research Scientist, Information Process Engineering (IPE) Tel : +49-721-9654-726 Fax : +49-721-9654-727 Email: michael.schneider@fzi.de WWW : http://www.fzi.de/michael.schneider ============================================================================== FZI Forschungszentrum Informatik an der Universität Karlsruhe Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe Tel.: +49-721-9654-0, Fax: +49-721-9654-959 Stiftung des bürgerlichen Rechts Stiftung Az: 14-0563.1 Regierungspräsidium Karlsruhe Vorstand: Dipl. Wi.-Ing. Michael Flor, Prof. Dr. rer. nat. Ralf Reussner, Prof. Dr. rer. nat. Dr. h.c. Wolffried Stucky, Prof. Dr. rer. nat. Rudi Studer Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus ==============================================================================
Received on Saturday, 30 July 2011 17:36:51 UTC