- From: pat hayes <phayes@ihmc.us>
- Date: Thu, 28 Aug 2003 09:24:28 -0700
- To: Jan Grant <Jan.Grant@bristol.ac.uk>, Olivier Corby <Olivier.Corby@sophia.inria.fr>
- Cc: www-rdf-comments@w3.org
>On Thu, 28 Aug 2003, Olivier Corby wrote: > >> >> In the RDF Test Cases >> http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-testcases-20030117/ >> the test case RDF + RDFS + DT(xsd:decimal, xsd:string) >> states that the following triples lead to a FALSE conclusion : >> >> ex:foo ex:bar "25"^^xsd:decimal >> >> ex:bar rdfs:range xsd:string >> >> >> >> Suppose the following triples, where there is now a resource ex:gee of >> rdf:type xsd:decimal, do they also lead to a FALSE conclusion ? >> >> >> ex:foo ex:bar ex:gee >> >> ex:gee rdf:type xsd:decimal >> >> ex:bar rdfs:range xsd:string > >That's an interesting case, and for an accurate answer I'll defer to the >Semantics document editor... Pat? Thanks, Jan; Hi, Olivier. The answer is NO, but a full explanation requires some subtlety. The actual conclusion here is that ex:gee has types both xsd:string and xsd:decimal. Now, that is impossible, of course, given the XSD spec, and an application which was sufficiently XSD-savvy might be able to recognize the implicit contradiction: but in fact it is not formally a contradiction in RDF itself, since RDF entailments about rdf:type are not required to be sensitive to information from external sources. In the case of a typed literal, however, the datatyping conditions may themselves access such external information to check typed literals. If the interpretation is XSD-sensitive in this way then the implicit contradiction will be made explicit by the datatype check. Hence the test case: note that it refers explicitly to the datatype mapping which includes the datatypes. As the semantics document states, these are the only contradictions recognized by RDF: without datatype checks, any RDF graph is consistent. Hope this helps. Pat >-- >jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/ >Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/ >(ECHOY GRUNTING) (EERIE WHISPERS) aren't subtitles great? -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Thursday, 28 August 2003 12:24:25 UTC