- From: Bijan Parsia <bparsia@cs.man.ac.uk>
- Date: Fri, 30 Jan 2009 16:51:14 +0000
- To: W3C OWL Working Group <public-owl-wg@w3.org>
On 21 Jan 2009, at 19:31, Bijan Parsia wrote: > Done with: > http://www.w3.org/2007/OWL/wiki/index.php? > title=Syntax&oldid=17348 [Bijan Parsia] > > To: > http://www.w3.org/2007/OWL/wiki/Syntax#Keys In working on the draft reply, I was wondering if my change was enough, or if it should read: """A key axiom of the form HasKey( owl:Thing OPE ) is similar to the axiom InverseFunctionalProperty( OPE ), the main differences being that the former axiom is applicable only to individuals that are explicitly named in an ontology, while the latter axiom is also applicable to individuals whose existence is implied by existential quantification. Furthermore, an inverse-functional property is inverse-functional for all assertions using that property, whereas keys can be scoped to assertions involving individuals of a certain class."""" Add: """In this way, classes can represent distinct tables with the same key name or different versions of the same table directly.""" If this is ok, I'll add it. Also, I think this is misleading: """This makes key axioms equivalent to a variant of DL-safe rules [DL- Safe]. Thus, key axioms will typically not affect class-based inferences such as the computation of the subsumption hierarchy, but they will play a role in answering queries about individuals. This choice has been made in order to keep the language decidable.""" DL safe rules require DL safety to be decidable (to a first approximation). Keys *do not*. We restrict keys for implementation considerations. Cheers, Bijan.
Received on Friday, 30 January 2009 16:47:47 UTC