- From: pat hayes <phayes@ai.uwf.edu>
- Date: Mon, 9 Dec 2002 18:44:44 -0600
- To: "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>
- Cc: www-webont-wg@w3.org
> > > > Jeremy's proposal is that OWL Lite be both a syntactic and *semantic* >> > > "subset" (I use the expression loosely in this case) of OWL DL. >> > >> > >> > Nothing loose there ... >> > my proposal views a language as a pair: >> > >> > < A set of documents, >> > an entailment relationship over the set > >> > >> > >> > Then >> > >> > OWL DL is a sublanguage of OWL full >> > in that the set of OWL DL documents is a subset of the set of OWL >Full >> > documents >> > the OWL DL entailment relationship is a subset of the OWL Full >> > entailment relationship (specifically the restriction of OWL Full >> > entailment to the set of OWL DL documents). >> >> Yes, so an OWL DL reasoner, when asked about entailment between two >> documents will either give the *SAME ANSWER* as an OWL full reasoner, >> or will refuse to answer on the grounds that the document is outside >> the subset it can handle. >> >> > >> > My OWL Lite is a sublanguage of OWL Full >> > the set of OWL Lite documents is a subset of the set of OWL Full >documents >> > the OWL Lite entailment relationship is also a subset of the OWL DL >> > entailment relationship. >> >> You have omitted the crucial fact that, in the case of your OWL Lite >> proposal, the entailment relationship is NOT the OWL full entailment >> relationship restricted to the set of OWL Lite documents, but is >> (probably) a subset of this set (intuitively tempting to believe that >> this is the case, but it remains to be proved). Thus, OWL Lite >> reasoners and OWL DL/full reasoners would give *DIFFERENT ANSWERS* to >> questions about entailment w.r.t. OWL Lite documents. >> >> This is *NOT* simply incompleteness w.r.t. OWL DL/full semantics, >> because a Lite reasoner would be entitled to answer NO to a question >> about entailment when the correct DL/full answer is YES. > >Fine, then it should not say NO, but > refuse to answer on the grounds > that the *entailment relationship* > is outside the subset it can handle. >(to slightly twist your words) >and that's just incompleteness Quite. So it might as well just admit that it is incomplete, and then we don't need to change the semantics. Considered as a DL it is going to be either incomplete or incorrect (considered as a subset of OWL Lite). Considered as a simple logic, it will be incomplete (considered as a subset of full OWL). Either way, it is going to be incomplete. Which is fine. Pat >-- , >Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/ -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes s.pam@ai.uwf.edu for spam
Received on Monday, 9 December 2002 19:45:13 UTC