Section Elements.
Ltac clean_eauto := unfold O.eqke, O.ltk; simpl; intuition; eauto.
Definition gtb (p p':key*elt) :=
match E.compare (fst p) (fst p') with GT _ => true | _ => false end.
Definition leb p := fun p' => negb (gtb p p').
Definition elements_lt p m := List.filter (gtb p) (elements m).
Definition elements_ge p m := List.filter (leb p) (elements m).
Hint Resolve gtb_compat leb_compat elements_3 : map.

Lemma elements_Add : forall m m' x e, ~In x m -> Add x e m m' ->
eqlistA eqke (elements m')
(elements_lt (x,e) m ++ (x,e):: elements_ge (x,e) m).