- From: Dan Connolly <connolly@w3.org>
- Date: 03 Jan 2002 13:32:44 -0600
- To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
- Cc: www-webont-wg@w3.org
On Thu, 2002-01-03 at 11:28, Frank van Harmelen wrote: > In an off-line email message, Jim wrote: > > > I'm curious about losing RDF-schema compatibility, of all of them, that seems > > like the simplest to preserve (esp. as we can still influence > > rdf-schema if minor changes to it fix this) > > Two reasons for only partial compatability: > - syntactic: we're not sure if we can organise the XML syntax to "include" a/some/all of the RDF Schema serialisations. Relax-NG seems like a pretty good mechanism for working with RDF, syntactically. cf http://www.w3.org/TR/2001/WD-rdf-syntax-grammar-20011218/#section-RELAXNG-Schema > - semantic: as you know, the RDF Schema model contains some oddities (classes as members of classes, etc). We might want to make the OWL meta-model simpler. Or we might want to work with the RDF Core WG to find something mutually agreeable. e.g. re classes as members of classes, this has been addressed to my satisfaction. I invite other folks to take a look: " 1.1 Technical Note We assume that there is no restriction on the domains and ranges of properties; in particular, a property may be applied to itself. When classes are introduced in RDFS, we will assume that they can contain themselves. This might seem to violate one of the axioms of standard (Zermelo-Fraenkel) set theory, the axiom of foundation, which forbids infinitely descending chains of membership. However, the semantic model given here distinguishes properties and classes as objects from their extensions - the sets of object-value pairs which satisfy the property, or things that are 'in' the class - thereby allowing the extension of a property or class to contain the property or class itself without violating the axiom of foundation." -- http://lists.w3.org/Archives/Public/www-archive/2002Jan/att-0007/01-RDF_Model_Theory.htm I have raised a related issue; I expect it to be addressed in this WG rather than in the RDF Core, but I'm happy for it to go either way... * vocabulary for traditional sets Dan Connolly (Tue, Nov 06 2001) http://lists.w3.org/Archives/Public/www-rdf-comments/2001OctDec/0210.html > > Frank. > ---- -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 3 January 2002 14:32:44 UTC