W3C home > Mailing lists > Public > www-rdf-logic@w3.org > April 2001

Re: semantics status of RDF(S)

From: <jos.deroo.jd@belgium.agfa.com>
Date: Mon, 9 Apr 2001 02:40:59 +0100
To: phayes@ai.uwf.edu
Cc: www-rdf-logic@w3.org, aswartz@swartzfam.com
Message-Id: <OF0BF44FFD.769B12D9-ON41256A29.00075034@bayer-ag.com>

> >When using resolution one cannot have such p->false rules.
> Incorrect. In fact, resolution REQUIRES the use of such clauses.

Of course it requires the use of such clauses, but only ONE
such clause, namely for the goal to be proved

> >So one cannot (as such) deny the fact that p is true.
> Yes, one can. If one could not deny it, resolution could never find a
> contradiction.

I could see the use of negation in the premises of rules
but not as
  false :- p
rules in a prolog program for instance
maybe I'm missing something in my knoledge of resolution ...

> >There is however an easier problem (maybe).
> >On the proof level (where proof expressions live)
> >we can discover that p has a no-proof-found value.
> >Of course that is not the denial of p but that
> >is not a problem for a proof expressions's life!
> >All it has to express is evidence that can be
> >syntactically checked to give semantic validity
> >(and such expressions can contain p->false
> >parts coming from negated premisses).
> I have no idea what you are talking about in the above paragraph. Can
> you rephrase it? In particular, what is the 'proof level' ?

The proof level is what TimBL has drawn so nicely in
I will rephrase my points later (I really have to sleep now ...)
(and really sorry for any confusion)

Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Sunday, 8 April 2001 20:41:11 UTC

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