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C00002 00002	Notes on Metaphysics
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Notes on Metaphysics

	Here is a new notion of situations unlike that in (McCarthy
and Hayes 1970) in two ways.

	First a situation is local, i.e. the situation in  New York
on New Years 1910.  Second, The situation itself doesn't carry
a value.  Instead a %2history%1 assigns values to fluents in
situations.  Thus we have %2value(Mayor(Newyork), newyork1910, h5)%1,
where ⊗h5 might be a certain hypothetical history in which the
South won at Gettysburg.

	Situations are subject to two partial orderings - temporal
and inclusional.  %2s1_<_s2%1 means ⊗s1 precedes ⊗s2 in time, and
%2s1_⊂_s2%1 means ⊗s1 is a subsituation of ⊗s2 in the sense that
the situation in Brooklyn is a subsituation of that in New York.
However, we envisage the inclusion relation being used for other
purposes than just spatial inclusion.