(** Def 5 of (Rose) *)

Definition Mod2_e : Cobham :=
  Rec
    Zero
    (False_e 2)
    (One_e 2)
    (One_e 1).

Lemma length_DivTwoPower : forall l, length (Sem DivTwoPower_e l) = length (hd nil l) - length (hd nil (tl l)).