- From: Drew McDermott <drew.mcdermott@yale.edu>
- Date: Sat, 8 Nov 2003 22:41:12 -0500 (EST)
- 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