(** * Minus (with reversed arguments)  - arities: (1,1) *)
Definition minus_rev_e : BC :=
rec (proj 0 1 0)
(comp 1 2 pred nil ((proj 1 2 1) :: nil))
(comp 1 2 pred nil ((proj 1 2 1) :: nil)).

Lemma minus_rev_correct :
forall m n, length (sem minus_rev_e [n] [m]) = (length m) - (length n).