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Re: the precondition property in OWL-S 1.0

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Sat, 8 Nov 2003 22:41:12 -0500 (EST)
Message-Id: <200311090341.hA93fCH29857@pantheon-po03.its.yale.edu>
To: public-sws-ig@w3.org

   [Bijan Parsia]
   There's two aspects of a precondition, its own logical form, and the 
   fact that it is embedded in larger conditional (effectively). So, if a 
   precondition is that <<My Credit line is greater than 1000>>, the form 
   of that assertion *could* just be a regular condition. and arguably 
   should be. It's the *relationship* between that formula and the process 
   that adds the extra semantics, much like putting a formula in the body 
   of a rule "changes" its semantics (*if* it is co-true with the other 
   atoms, then the consequential atoms must be true).

Actually, when semantics is done right, the context of a formula
doesn't add any "extra semantics."  All the meaning of (if P Q) can be
factored into the meaning of P, the meaning of Q, and the meaning of
(if _ _).

I sort of thought the Precondition class was essentially a typo -- a
side effect of too many cooks stirring that particular soup.  Why are
we defending its existence?

                                   -- Drew McDermott
                                      Yale Computer Science Department
Received on Saturday, 8 November 2003 22:41:14 UTC

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