- From: Michael Schneider <m_schnei@gmx.de>
- Date: Wed, 07 Mar 2007 23:10:17 +0100
- To: pratt@cs.stanford.edu
- CC: semantic-web@w3.org, public-owl-dev@w3.org, bparsia@cs.man.ac.uk
Vaughan Pratt wrote on Wed, 07 Mar 2007: > Bijan Parsia wrote: >> Well, disjointness is *weaker* than full negation. For example, in OWL, >> A disjointWith B is just syntactic sugar for A subclassof complementOf(B). > > Are there technical (e.g. computational complexity) benefits to this > definition over the more usual (and more constructive) definition in > terms of emptiness of intersectionOf(A,B)? Thanks, Vaughan! That's an even more obvious example, how one can simulate a disjointness axiom between two classes A and B within OWL-/Lite/. Restated: EquivalentClasses(owl:Nothing intersectionOf(A B)) 'owl:intersectionOf' is explictly allowed vocabulary within OWL-Lite, as long as the classes mentioned are named classes (or restrictions), see http://www.w3.org/TR/2004/REC-owl-features-20040210/#intersectionOf Bijan's 'complementOf' construction only works in OWL-DL, where 'owl:disjointWith' is given anyway. (But to be fair, keeping within OWL-Lite wasn't the topic in Bijan's cited explanation - this first came up in a later mail). Cheers, Michael
Received on Wednesday, 7 March 2007 22:10:22 UTC