Opaque Length_e.
(** Def 7 of (Rose) *)
Definition MultOneMinus'_e : Cobham :=
Comp 2 Cond [
Proj 2 1;
Proj 2 0;
Zero_e 2;
Zero_e 2
].

Lemma MultOneMinus'_correct : forall l,
hd nil (tl l) = nil \/ bs2nat (hd nil (tl l)) <> 0 ->
bs2nat (Sem MultOneMinus'_e l) = bs2nat (hd nil l) * (1 - bs2nat (hd nil (tl l))).