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Re: Preconditions /effects vs Preconditions/Postconditions

From: Sheila McIlraith <sam@ksl.Stanford.EDU>
Date: Mon, 15 Sep 2003 11:21:36 -0700 (PDT)
To: David Martin <martin@AI.SRI.COM>
Cc: Monika Solanki <monika@dmu.ac.uk>, <www-ws@w3.org>
Message-ID: <Pine.GSO.4.44.0309151107200.27852-100000@ksl.Stanford.EDU>

On Mon, 15 Sep 2003, David Martin wrote:

> Monika Solanki wrote:


> >
> > The ambiguity in thinking about it in this way is that the "Effect" part
> > maps to  "Thing", while only the "Condition" part maps to  "Condition".
> > This is also what I had mentioned  in the first or second email of this
> > thread. Is this "Effect part" a logical formulae, if it is the same as a
> > condition? If it were indeed to be , then I believe, that ceEffect
> > should map to "Condition" as well
> I agree that Condition should be the range of ceEffect.  I expect we
> will be discussing this soon, in the context of a larger range of issues
> about conditions and effects.

I don't agree with this.  In its most general form, an effect can be any
well-formed formula (wwf). In such a case, the range of ceEffect should be
a class called "Wff".  I think it furthers the terminology confusion that
we've been seeing on this list to refer to the range as "Condition".  A
"condition" is indeed a "Wff" as well, but it plays a particular role,
which is why it has a different name.  FYI, in the original DAML-S, we
agreed to adopt the convention of PDDL that the effects (ceEffect) would
be interepreted as a conjunction of literals, i.e., a restricted wff.

You don't see "Wff"  in DAML-S because we had no way of defining
arbitray well-formed formulae in DAML-S.  As David Martin noted, with
DRS (contained in the appendix of the DAML-S release) we can now define
some logical formulae.  Nevertheless, DRS is not part of the bona fide
release, so we do not use "Wff" etc. as a ranges in the release.



Sheila McIlraith, PhD                 Phone: 650-723-7932
Senior Research Scientist             Fax:  650-725-5850
Knowledge Systems Lab
Department of Computer Science
Gates Sciences Building, 2A-248       http://www.ksl.stanford.edu/people/sam
Stanford University                   E-mail: sam-at-ksl-dot-stanford-dot-edu
Stanford, CA 94305-9020
Received on Monday, 15 September 2003 14:21:56 UTC

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