(* resource coherence *)

(* FIXME: put somewhere else. *)
Definition fmap_option {A B} (v: option A) (m: B) (f: A -> B): B :=
  match v with
    | None => m
    | Some v' => f v'
  end.

Lemma ghost_of_make_rmap: forall f g lev H Hg, ghost_of (proj1_sig (make_rmap f g lev H Hg)) = g.