Program: Let c be an arbitrary SIMPL program and assume that judgment ßs' holds for some store s'. Prove by structural induction that x Î pre(s'), where pre(s') denotes the preimage of s'.
I looked up the definition of pre-image:
f: X®Y
x ? X is a pre-image of y ? Y if (y,x) ? ? (? is a binary relation)
What should my recursive case be?