- From: Toby Inkster <tai@g5n.co.uk>
- Date: Fri, 02 Oct 2009 09:10:48 +0100
- To: Kevin Tyson <kevin.tyson@gmail.com>
- Cc: Bernard Vatant <bernard.vatant@mondeca.com>, semantic-web@w3c.org
On Thu, 2009-10-01 at 19:16 -0400, Kevin Tyson wrote: > What I don't understand is why an instance of the covered class does > not create an inconsistency. It's a consequence of the open world assumption. If I define: :Primate owl:equivalentClass [ owl:unionOf (:Human :Monkey) ] . :Human owl:disjointFrom :Monkey . (And I realise I'm vastly oversimplifying the biology here!) then a statement like this: :Bob rdf:type :Primate . is not inconsistent. In the first snippet, you've asserted that all primates must be human or monkey, and cannot be both. In the second, you've asserted that Bob is a primate. Therefore, Bob must be human or a monkey, but not both. But because of the open world assumption, that's OK. Bob *is* either a human or a monkey, and not both - but we haven't said which he is. -- Toby A Inkster <mailto:mail@tobyinkster.co.uk> <http://tobyinkster.co.uk>
Received on Friday, 2 October 2009 08:11:29 UTC