- From: Jeremy Carroll <jjc@hpl.hp.com>
- Date: Wed, 14 May 2008 19:24:50 +0100
- To: Evren Sirin <evren@clarkparsia.com>
- CC: public-owl-dev@w3.org
Sorry for the delayed reply. Thanks, the linked paper is interesting, and then I am thinking I asked the wrong question ... If I read about Pellet at say: http://pellet.owldl.com/features I find features such as [[ Classification Computes the subclass relations between every named class to create the complete class hierarchy. The class hierarchy can be used to answer queries such as getting all or only the direct subclasses of a class. Realization Finds the most specific classes that an individual belongs to; i.e., realization computes the direct types for each of the individuals. Realization can only be performed after classification since direct types are defined with respect to a class hierarchy. Using the classification hierarchy, it is also possible to get all the types for each individual. ]] that correspond to say the if-and-only-if conditions on rdfs:subClassOf. & Pellet, when doing these tasks, at some abstract level, spontaneously generates/finds these relationships. At least abstractly we could do a "Propertification" that arranges the properties in their hierarchy too, by for every pair p,q of properties asking Pellet if an ontology O entails (p subPropertyOf q), and this could be, in principle, annotated with inverseOf links, and Functional, IFP, Symmetric, Transitive labels ... It doesn't feel useful though! Jeremy Evren Sirin wrote: > > On 5/6/08 7:23 AM, Jeremy Carroll wrote: >> >> >> >> I've being looking in depth at the OWL 1 Full semantics (again, sigh) ... >> >> I note that the classes of properties (FP,IFP, SP, TP) and the >> inverseOf property all have iff definitions. These correspond to the >> conditions in the direct semantics. >> >> Is it the case that DL reasoners can actually answer entailment >> questions depending on this e.g. >> >> If C is a class consisting of a singleton, and p is a property with >> domain and range C, then we necessarily have that p is in FP, IFP, SP >> and TP and that p is its own inverse. >> Moreover if q also has domain and range p, and both q and p are non >> empty then they are equivalentProperties, and also each others inverse. >> >> Do DL reasoners answer these sorts of question? > > Yes, DL reasoners can answer such entailment queries. Any OWL entailment > query can be reduced to an unsatisfiability check in DL reasoning as > shown in [1]. Pellet supports these kind of queries. For example, browse > a similar ontology [2] in OwlSight [3] and the inferences for the > property will be listed (in this example only symmetry and functionality > is inferred from asserted axioms). > > Cheers, > Evren > > [1] http://www.comlab.ox.ac.uk/people/ian.horrocks/Publications/#HoPa04b > [2] http://www.w3.org/2002/03owlt/SymmetricProperty/premises002.rdf > [3] > http://pellet.owldl.com/owlsight/?ontology=http://www.w3.org/2002/03owlt/SymmetricProperty/premises002.rdf > >> >> Ta >> >> Jeremy >> >> >> >> > >
Received on Wednesday, 14 May 2008 18:26:24 UTC