> Quick terminology question on CS 655 HW3:  What does it mean for an
> opsem rule of inference to have a "fixed set of hypotheses?"  The term
> is used in Exercise 4.

You cannot invent an opsem rule where the number of hypotheses somehow
depends on the conclusion. Every opsem rule should have a small, fixed
number of hypotheses (typically at most 3 or 4). For example, you might
have been tempted to make a WHILE rule like this:

 < b, s> V true  < c, s_0 > V s_1  < b, s_1 > true ... < b, s_i > false
 ----------------------------------------------------------------------
 < while b do c, s> V s_i

... where the rule itself somehow "unrolls" the while loop until it is
done. Don't do that -- the rule does not have a "fixed set of hypotheses".

        - Wes