- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Tue, 23 Apr 2002 03:20:19 -0400
- To: jjc@hplb.hpl.hp.com
- Cc: www-webont-wg@w3.org
From: "Jeremy Carroll" <jjc@hplb.hpl.hp.com> Subject: RE: SEM: comprehensive entailments without dark triples Date: Mon, 22 Apr 2002 17:28:12 +0100 > > > > The problem with these comprehension principles is that they do not > > generate non-tree structures. Therefore classes that are not in the form > > of trees (yes, this is rather vague, but my previous message gives one > > example) will not be consequences. > > > > I agree, that was an objective. > > Jeremy Huh? Do you mean that classes that are not in the form of trees will not be consequences? This leads to what is to me a very strange logical system in which the comprehension principle only works for some kinds of restrictions. Consider the following KB: KB1: John rdf:type Person . John rdf:type :_1 . :_1 daml:onProperty child . :_1 daml:cardinality "0" . As John has no children it seems to me that it should be a theorem of the logical system that John belongs to any value restriction on child. However, this is not the case. Consider the following KBs: KB2: :_2 daml:onProperty child . :_2 daml:toClass Person . KB3: :_3 daml:onProperty child . :_3 daml:toClass :_3. KB1 entails KB2, but does not entail KB3. peter
Received on Tuesday, 23 April 2002 03:21:32 UTC