proposition: Lemma s_zero_fun : functional s_zero.
proof: Proof. intros v x y Hx Hy; rewrite Hy; trivial. Qed.
imports: Arith Lia List Bool Eqdep_dec Undecidability.Shared.Libs.DLW(utils_tac utils_nat utils_list finite pos vec) Undecidability.MuRec.MuRec