fact: Definition s_rec f h v := μ_rec (f (vec_tail v)) (fun x y => h (x##y##vec_tail v)) (vec_head v).
imports: Arith Lia List Bool Eqdep_dec Undecidability.Shared.Libs.DLW(utils_tac utils_nat utils_list finite pos vec) Undecidability.MuRec.MuRec