- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Thu, 19 Sep 2002 08:03:50 -0400
- To: Ian Horrocks <horrocks@cs.man.ac.uk>
- Cc: www-webont-wg@w3.org
At 12:53 PM +0100 9/19/02, Ian Horrocks wrote: >This is *NOT* a proposal, half baked or otherwise. It is just a report >on (possibly) relevant ongoing research (my reluctance to provide such >a report was exactly because I was worried that it might be >interpreted as a proposal). I never interpreted what you said as a proposal. I made the proposal below and only had it attached to your mail because it followed in the thread - I should have given it a new title -- something like "An approach to issue 5.1" instead of making it look like it was a continuation on your previous mail. I apologize for the confusion. I take it from the message I'm responding to that you don't approve of the below - but please argue it on its own merits -- that is, given there are members of the group who cannot live with the daml+oil situation, and given the D+O group expliciely said this was an issue that should be revisited, I think it is incumbent on the working group to consider new proposals. Dan C sent the "States" use case which he believes important, and I heard a number of people agree. Dan's proposal is to drop the distinction all together. I think the below addresses his issue in a way I hope he could live with, and it provides a syntactic hook by which you could say clearly in your documents that if an ontology uses this specific syntactic feature then they lose completeness/decidability (or whatever the specific consequence is) - meaning you could do a syntactic check to see if an ontology contained it (and give appropriate warning), rather than having to reason about whether things are data or objects. Again, I do offer this as a strawman, I'd like to see the group converge on something which everyone can live with (even if no one prefers it) and I hope this is a starting place for discussion - if anyone has a better compromise solution, please put it forth. -JH > > > >> I think some sort of compromise is needed, here is a half-baked >> proposal that might be useful in continuing the discussion >> >> Suppose we continue to have data and object properties distinguished, >> but with some sort of syntactic construct that would let one do an >> association that allows keys- as follows: >> >> :SSnum a owl:dataTypeProperty. >> :Individual a owl:class. >> :Individual a owl:ObjectTypeProperty. >> :SSnum owl:dataDesignatesUniqueObject :Individual. (needs a better name) >> >> which would be a syntactically special way to say inverseFunctional >> on a datatype. (This would allow keys and some other similar uses). >> The advantage is that there would be a syntactic flag to know this is >> occuring so that Fact and other reasoners could say "If you use this >> property, you may not get completeness" -- in short, this is a >> variant on Jeremy's "here be dragons" approach -- but since, at least >> I think, the inverseFunctional on datatypes would mostly be used by >> people doing things to instances (rather than class reasoning) this >> wouldn't be a major problem. >> Dan's states examples seem to be satisfied by this (details left as >> exercise to reader) and it also allows distinguished data and type >> classes for tools like RIC that can profit from knowing which is >> which. >> >> -JH >> p.s. Please note this message doesn't say "chair neutrality off" - >> I'm not putting forth my personal preference here, but trying to get > discussion restarted. -- 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 Thursday, 19 September 2002 08:04:10 UTC