- From: Jos De_Roo <jos.deroo@agfa.com>
- Date: Thu, 24 Jul 2003 01:07:25 +0200
- To: pfps@research.bell-labs.com
- Cc: jjc@hpl.hp.com, www-webont-wg@w3.org, www-webont-wg-request@w3.org
Peter F. Patel-Schneider wrote: > From: Jeremy Carroll <jjc@hpl.hp.com> > Subject: TEST: 6 of 7: empty universe example, > Date: Wed, 23 Jul 2003 19:20:15 +0300 > > > > > Peter? > > (for book-keeping) > > > > I had some outstanding actions on this one. > > > > At one point it seemed that I would need to make owl:Thing finite but > > non-empty to get different behaviour in DL and Full; it now appears that > > owl:Thing can be empty in DL, os I have reduced the test to > > > > owl:Thing owl:equivalentClass owl:Nothing > > > > http://www.w3.org/2002/03owlt/editors-draft/draft/proposedByFunction#Thing-001 > > http://www.w3.org/2002/03owlt/editors-draft/draft/proposedByFunction#Thing-002 > > > > this test is slightly different from the one that I was actioned to produce. > > > > Jeremy > > Hmm. There may have been a slight glitch here at some time. > > Right now, neither the direct semantics nor the rdfs semantics require that > the OWL DL universe of discourse is non-empty. > > As Pat pointed out empty universes can cause problems in languages with > quantification. I don't think that these problems surface in OWL. I really can't make any sense of following being consistent [[ <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:owl="http://www.w3.org/2002/07/owl#" xml:base="http://www.w3.org/2002/03owlt/Thing/consistent001" > <owl:Class rdf:about="http://www.w3.org/2002/07/owl#Thing"> <owl:equivalentClass rdf:resource ="http://www.w3.org/2002/07/owl#Nothing"/> </owl:Class> </rdf:RDF> ]] which is basically and globally the content of http://www.w3.org/2002/03owlt/Thing/consistent001 (but it's currently forbidden to access it and maybe it better stay's like that ;-)) > peter -- Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Wednesday, 23 July 2003 19:24:12 UTC