[CST-2] OptComp 93/9/6

[M.Y.W.Y. Becker]

Has anyone done this (rather hard) question?

Is this correct?
(a)
VB(n) = empty if succ(n)=empty
VB(n) = INTERSECTION over succ(n):
        VB(s) UNION gen(s) \ kill(s), o/w
where
gen(s) = set of expressions freshly computed at s
kill(s) = set of expressions containing vars modified at s

(b)
* backwards flow equation
* neither VB(n)<=AVAIL(n) nor the other way round
* what else???

(c) as usual, find max. fixed point of continuous transformation on finite 
lattice by repeated application etc.

Second part: ???
If f is strict in y it doesn't necessarily mean that y is very busy 
somewhere.
If y is very busy somewhere it doesn't necessarily mean that f is strict in 
y.
So what's the relation between strictness and very-busy-ness?


Mo