Definition f'_else :=
comp2Ss h0 [proj2n 1]
([comp2Ss Y_e [proj2n 0; proj2n 1] [proj2Ss 3];
proj2Ss 2 ] ++ (map (proj 2 (S sl)) (seq 4 (sl - 1)))).

Lemma f'_else_inf : arities f'_else = ok_arities 2 (S sl).
Opaque f'_else.