- From: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>
- Date: Mon, 20 May 2002 23:16:12 +0200
- To: pfps@research.bell-labs.com
- Cc: "www-webont-wg" <www-webont-wg@w3.org>
[...]
> > I also use modus tollens (actually resolution)
> > quite a lot inside the engine, but it's not safe
> > I think as outside (non-closed world) evidence.
> >
> > --
> > Jos
>
> How is modus tollens unsafe?
I think the trouble starts with your rule
?x a ?y, ?x a [owl:complementOf :y] -> FALSE
We can't assert such a rule with a conclusion
that is FALSE (as it is not a Horn clause).
We would rather write a rule like
{ :rule16c1 . ?x a ?y . ?x a ?z . ?y owl:complementOf ?z }
log:implies { ?x :inconsistentWith owl:complementOf } .
so have the inconsistency detected explicitly
and that would not mean discharging assumptions.
> peter
--
Jos
Received on Monday, 20 May 2002 17:16:50 UTC