fact: Definition fib_inv (n x y : ptr) (N : nat) h : Prop := exists n' x' y': nat, [/\ h = n :-> n'.+1 \+ x :-> x' \+ y :-> y', x' = fib_pure n' & y' = fib_pure (n'.+1)].
imports: mathcomp(ssreflect ssrbool ssrnat eqtype seq ssrfun) fcsl(prelude pred pcm unionmap heap) HTT(stmod stsep stlog stlogR)