W3C home > Mailing lists > Public > www-webont-wg@w3.org > May 2002

Re: ISSUE: DAML+OIL semantics is too weak

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>
Message-ID: <OF52D466C1.18F6C892-ONC1256BBF.0071E6B8@agfa.be>

[...]

> > 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 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:57:50 GMT