(** * Recursion on the result of the function [x], with one function [h] taking [i] instead of two function [h]_[i] *)
Definition rec3 n s x g h : BC :=
comp n s
(rec1 n s g h)
(x ::
map (proj n 0) (seq 0 n))
(map (proj n s) (seq n s)).

Lemma arities_rec3 n s x g h
(Hx : arities x = ok_arities n 0)
(Hg : arities g = ok_arities n s)
(Hh : arities h = ok_arities (S n) (S s)) :
arities (rec3 n s x g h) = ok_arities n s.