- From: Ian Horrocks <horrocks@cs.man.ac.uk>
- Date: Tue, 24 Sep 2002 17:26:34 +0100
- To: pat hayes <phayes@ai.uwf.edu>, www-webont-wg@w3.org
Pat, DAML+OIL, and I hope OWL, can be viewed a fragment of FOL, with atomic classes and properties corresponding to unary and binary predicates respectively. According to this correspondence, subClassOf axioms become implications, e.g., A subClassOf B corresponds to: forall x . A(x) -> B(x) Similarly, a property range axiom P range A corresponds to: forall x,y P(x,y) -> A(y). What could be simpler and clearer than that? The combination of these two sentences entails forall x,y P(x,y) -> B(y). What could be simpler and clearer than that? If you want some alternative semantics, could you please explain in similar terms what it is? Ian p.s. In DAML+OIL, and I hope in OWL, it has long been recognised (I'm sure it is written down in the documentation somewhere) that range is just syntactic sugar, and that P range A could be re-written as: Thing subClassOf Restriction (onProperty P) (allValuesFrom A) with the same result as above, i.e., this axiom plus A subClassOf B clearly entails: Thing subClassOf Restriction (onProperty P) (allValuesFrom B)
Received on Tuesday, 24 September 2002 11:29:36 UTC