- From: Mike Smith <msmith@clarkparsia.com>
- Date: Wed, 18 Feb 2009 10:19:51 -0500
- To: W3C OWL Working Group <public-owl-wg@w3.org>
Dear Mike, Thank you for your message http://lists.w3.org/Archives/Public/public-owl-wg/2009Jan/0031.html on the OWL 2 Web Ontology Language last call drafts. The OWL Direct Model-Theoretic Semantics [1] defines entailment in terms of interpretations and requires that all URIs in an ontology are present in the vocabulary of any interpretation satisfying that ontology. The OWL 2 Direct Semantics [2] document defines entailment in terms of models, a change which relaxes the vocabulary constraint. The change is intentional -- it is useful because it permits tautologies to be entailed by the empty ontology and simplifies the semantic specification. The difference is demonstrated by the test case you have cited [3]. This test is a positive entailment under the OWL 2 Direct Semantics, but was a negative entailment under the OWL Direct Model-Theoretic Semantics used when the WebOnt WG approved the test case. The definition of entailment in the OWL 2 Direct Semantics document will not be changed in response to your comment. -- Mike Smith Clark & Parsia [1] http://www.w3.org/TR/owl-semantics/direct.html [2] http://www.w3.org/2007/OWL/wiki/Direct_Semantics#Inference_Problems [3] http://www.w3.org/2002/03owlt/Class/Manifest005#test
Received on Wednesday, 18 February 2009 15:20:32 UTC