(** * Conversions between maps and association lists. *)
Definition of_list :=
List.fold_right (uncurry (@add _)) (empty elt).
Definition to_list := elements.

Lemma of_list_1 : forall l k e,
NoDupA eqk l ->
(MapsTo k e (of_list l) <-> InA eqke (k,e) l).