- From: Christopher Welty <welty@us.ibm.com>
- Date: Wed, 28 Aug 2002 17:36:08 -0400
- To: Dan Connolly <connolly@w3.org>
- Cc: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com>, www-webont-wg@w3.org, www-webont-wg-request@w3.org
Dan, You've lost me - I don't understand why you think dropping "equivalentTo" will prevent you from specifying unique mappings from "property" values to individuals, ie. a 1:1 mapping from a state code to a state. If, in your example, statecode is a "owl:property" that is both functional and inversefunctional, you will get this mapping. Is that not what you want? -ChrisW Dr. Christopher A. Welty, Knowledge Structures Group IBM Watson Research Center, 19 Skyline Dr. Hawthorne, NY 10532 USA Voice: +1 914.784.7055, IBM T/L: 863.7055 Fax: +1 914.784.6078, Email: welty@us.ibm.com Dan Connolly <connolly@w3.org> Sent by: www-webont-wg-request@w3.org 08/28/2002 01:09 PM To: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com> cc: www-webont-wg@w3.org Subject: Re: proposals for the underlying principles of OWL On Wed, 2002-08-28 at 11:38, Peter F. Patel-Schneider wrote: [...] > How the issues are resolved can only be completely determined by > understanding the various documents. However, the basics are as follows: The progress on semantic layering looks interesting... > Issue 5.3 Semantic Layering > The semantic layering of OWL on top of RDFS is that OWL is a theory > in an extension of RDFS. In this theory, the OWL domain of > discourse is not the entire RDF domain of discourse. but the features of the language you're talking about are very different from the features I'm interested in: > > Issue 4.6 EquivalentTo > EquivalentTo is removed from the language, as it is ill-typed. > Issue 5.1 Uniform treatment of literal/data values > There is a strict separation between OWL object and data values. > Removing the separation has computational consequences. I'm not interested in a language like that. The most important feature of the ontology layer, for me, is daml:UnambiguousProperty, as specified by the axiomatization. i.e. the ability to say "if X and Y have the same state code, they're the same thing." (for details, see these test materials: http://www.w3.org/2002/03owlt/sameStateP.rdf http://www.w3.org/2002/03owlt/sameStateC.rdf ) I've seen suggestions that WebOnt should persue the description logic features (tractable inference etc.) but some of the useful looking features of DAML+OIL (UnambiguousProperty, equivalentTo) should be added to RDFS. Those properties were in earlier drafts of RDFS, after all; they were left out because the WG wasn't clear on how to formalize them. But now that we've got a formal understanding of how RDFS works, it's no problem to add them. I was thinking of this WG as the group to add those features back on top of RDFS, but maybe that's not what folks want to do. -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 28 August 2002 17:37:13 UTC