Definition A2P {A} :=
 (fun (pmap : access_map) (a : address * A) =>
      let (a0, _) := a in let (b0, ofs0) := a0 in setPermBlock (Some Writable) b0 ofs0 pmap LKSIZE_nat).

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).