End Elt.
#[global]
Hint Constructors avl : core.
Section Map.
Variable elt elt' : Type.
Variable f : elt -> elt'.

(* Specifications: *)
Lemma map_height : forall m, height (map f m) = height m.
Lemma map_avl : forall m, avl m -> avl (map f m).
End Map.