fact: Definition vrf' (e : ST A) i (Q : post A) := forall (V : valid i), exists (pf : i \In pre_of e), forall y m, prog_of e _ V pf y m -> Q y m.
imports: mathcomp(ssreflect ssrbool ssrfun ssrnat eqtype seq) pcm(options axioms pred prelude) pcm(pcm unionmap heap) htt(domain)