• From: Ian Horrocks <horrocks@cs.man.ac.uk>
• Date: Wed, 29 Oct 2003 23:51:50 +0000
• To: www-webont-wg@w3.org
• Message-ID: <16288.21142.582775.508275@merlin.horrocks.net>

Further to my earlier emails regarding ontologies that force and empty
universe of discourse. I propose that we augment the definition of an
Abstract OWL interpretation in Section 3 of S&AS with the condition
that EC(owl:Thing) is a non-empty set (we already have that R, the
resources of I, is a non-empty set). This would have the benefit that:

- axioms such as "A implies not A" would be considered inconsistent
(currently this is consistent).

- ontology consistency in OWL DL would be equivalent to the
consistency of the class Thing (using the standard definition of class
consistency);

- an OWL DL ontology would be inconsistent just in case the
corresponding FO theory entails false;

- an OWL DL ontology would be inconsistent just in case the
corresponding SHOIQ(Dn) knowledge base is inconsistent.

Regards, 

Ian

Received on Wednesday, 29 October 2003 18:56:39 UTC