- From: Bijan Parsia <bparsia@cs.man.ac.uk>
- Date: Thu, 28 Aug 2008 10:51:19 +0100
- To: Alan Ruttenberg <alanruttenberg@gmail.com>
- Cc: "Boris Motik" <boris.motik@comlab.ox.ac.uk>, "'W3C OWL Working Group'" <public-owl-wg@w3.org>
On 28 Aug 2008, at 09:49, Alan Ruttenberg wrote: > On Aug 28, 2008, at 10:26 AM, Boris Motik wrote: > >> Hello, >> >> They could; however, the existing way of handling things is >> deliberate, as it makes the structural specification more uniform. > > Uniform in what way? I would think that having global restrictions > be truly global would be a clearer benefit if sensibility of the > spec is a desirable. > >> Furthermore, as already discussed, there is no observable >> difference between the Skolem semantics and the existential one >> for all >> inference problems apart from certain entailments, which DL users >> are typically not interested in anyway. In such cases, without >> changing the set of "interesting" consequences, one can skolemize >> the anonymous individuals; but then, one can freely drop the >> global restrictions altogether without funning into decidability >> problems. The way resolution of ISSUE-118 has been implemented >> allows precisely for that: a tool can simply forget about Global >> Restrictions 4 and 5 and obtain a language that can be interpreted >> under the Skolem semantics for all practical intents and purposes. > > Yes, but what language would that be? Why would we want to enable > that? Skolem semantics isn't an option we support in any of our > profiles. We need it for 1) SPARQL/OWL and 2) for closer alignment with existing RDF and OWL implementation behavior. Indeed, although I'm not happy with this outcome (since I believe skolemesque semantics are the right one) I'm more comfortable with it when presented in this way. Cheers, Bijan.
Received on Thursday, 28 August 2008 09:48:50 UTC