- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Mon, 12 May 2003 09:00:08 -0400
- To: Ian Horrocks <horrocks@cs.man.ac.uk>
- Cc: webont <www-webont-wg@w3.org>
My bad for forgetting that same was transitive and that we would need four constructs. I can write an answer to that one. For the person who asked for allDisjoint, can someone see if they can find the WG's discussion on this and craft a response? Any volunteers -JH At 10:14 +0100 5/12/03, Ian Horrocks wrote: >On May 11, Jim Hendler writes: >> >> We have received a couple of comments that we should have some other >> constructs similar to allDifferent >> one comment suggest AllSame >> another asks for AllDisjoint >> >> we need an answer as to why we included the first and not the latter >> two, or we need to decide our current mechanism could be extended to >> allow it to be used on other properties (which would probably not >> require another LC if we make it clear this is just a piece of >> syntactic sugar since we have the appropriate semantics already). > >As Jeremy points out, the various "same" relations are transitive, so >there is no n^2 blowup in the number of property relationships >required to express them, and the result is more compact than a (fully >expanded) list would be. > >I also agree with Jeremy's account of the WG's thinking >w.r.t. disjoint classes - that it is much less frequently required, >and that the numbers (of classes) involved would typically be small >(compared to unique individuals). It was therefore decided that >additional syntax was not justified. > >W.r.t. disjoint properties, I'm not sure we even considered it. It is >rarely asked for, and unlike the class/individual cases it is >relatively difficult to express in the existing language given >that we don't have property negation. > >Ian > > > > > >> >> Any thoughts? -- Professor James Hendler hendler@cs.umd.edu Director, Semantic Web and Agent Technologies 301-405-2696 Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) Univ of Maryland, College Park, MD 20742 240-731-3822 (Cell) http://www.cs.umd.edu/users/hendler
Received on Monday, 12 May 2003 09:00:29 UTC