- From: pat hayes <phayes@ai.uwf.edu>
- Date: Fri, 27 Sep 2002 22:54:19 -0500
- To: "Christopher Welty" <welty@us.ibm.com>
- Cc: www-webont-wg@w3.org
>(This may sound like I'm speaking for Pat, but actually I'm trying to >verify if I understand his position) Heaven forfend that you should ever find yourself speaking for me, Chris. > >I think what I'm getting out of trying to ingest the discussion is that >Pat wants the semantics of ranges to be something like, in a "free >wheeling" syntax: > >Property(p) -> EXISTS c . Class(c) AND Range(p,c) >Property(p) AND Range(p,c1) AND Range (p,c2) -> c1=c2 >p(x,y) AND Range(p,c) -> c(y) > >So he wants there to be one and only one class that is THE range of a >property. No, no. Im sorry I ever said this awful thing. I was trying to convey an intuition but I did it badly. Better, what Im trying to say is that I want it to be possible to have a *particular set* of ranges. I don't mind if that set is closed under intersections, even. But I do mind if Im forced to say that a set is a range just because all the values of the property are in it. That should be a necessary but not sufficient condition to be a range. I want it to be possible to restrict rangehood to some special class of classes. > Your entailment below should still be OK, ie > >Subclass(c1,c2) AND Range(p,c1) AND p(x,y) |= c2(y) > >BUT NOT: >Subclass(c1,c2) AND Range(p,c1) |= Range(p,c2) Right on that. > >If this is an accurate account of Pat's position, then the argument >against the entailments in OWL regarding superclasses of property ranges >is that it abuses the Range relation between a property and a class, and >violates the uniqueness axiom above. The former, yes; latter, no. Never mind about uniqueness, sorry I ever gave that impression. Pat -- --------------------------------------------------------------------- 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
Received on Friday, 27 September 2002 23:54:02 UTC