- From: Jeremy Carroll <jjc@hpl.hp.com>
- Date: Tue, 11 Dec 2007 10:06:14 +0000
- To: Alan Ruttenberg <alanruttenberg@gmail.com>
- CC: Michael Schneider <schneid@fzi.de>, Owl Dev <public-owl-dev@w3.org>, hendler@cs.rpi.edu, boris.motik@comlab.ox.ac.uk, pfps@research.bell-labs.com, ian.horrocks@comlab.ox.ac.uk, dlm@ksl.stanford.edu, hans.teijgeler@quicknet.nl
Alan, if Michael is wrong in the way that you suggest, it should be possible to construct a very small counter-example illustrating his mistake. I believe that the text you give purports to be a recipe for this counter-example; but I take your recipe book into my kitchen, and I end up spilling my triples on the floor. So would you mind baking the example for me, Ahhh - I should clearly state the properties this example would have - but I'm not going to manage that today thanks Jeremy Alan Ruttenberg wrote: > > Here's my understanding of the situation (if I've got it wrong > somewhere, please correct me). > > On Dec 8, 2007, at 3:20 PM, Michael Schneider wrote: > >> But, AFAICS, this would only become a real problem, if in this >> ontology some class is used as an individual (metamodelling). > > Or if the class has instances that are literals. > >> But in such a case, even after changing rdfs:Class to owl:Class, the >> resulting ontology would still be an OWL-Full ontology: There would, >> for example, be an 'rdf:type' triple with some class being at the >> individual position, or a class with an object or data property >> attached. > > The type triple is inferred in OWL Full - it doesn't have to be explicit. > >> The OWL-DL reasoner would refuse to work in such a situation, of course. > > Because the triple would sometimes need to be inferred by the reasoner > itself, the DL reasoner can't detect the situation in all cases. > Strictly speaking, it can only detect the case where it certainly > shouldn't work. > >> So it looks to me that this recommendation is safe. > > I would say, no. However it might be ok if the user was warned, or made > an explicit declaration to that effect. > >> Or to summarize these recommendations in a simple rule of thumb: >> Assume 'rdfs:Class' in RDFS ontologies, assume 'owl:Class' in OWL >> ontologies. > > How do you tell the difference between and RDFS ontology and and OWL > ontology? > > I think what might "work" is commonly called "duck typing", as in, if it > walks like a duck and quacks like a duck, then.... > > The application in this case would be to look for an *explicit* mention > of something that might be only *inferred* in an OWL Full ontology. > Absent the explicit mention, you might assume that that the author did > not intend there for such statements to be inferred either. This would > be a change from the current semantics, and possibly a reasonable ones, > depending, IMO, on how the OWL Full advocates voted. > > -Alan > >
Received on Tuesday, 11 December 2007 10:06:48 UTC