Definition PMap_eq {A} (m m' : PMap.t (Z -> A)) := forall b' ofs', m !! b' ofs' = m' !! b' ofs'.

Lemma fold_right_cons : forall A B (f : A -> B -> B) (z : B) (x : A) (y : list A),
fold_right f z (x :: y) = f x (fold_right f z y).