proposition: Fact finite_t_map X Y (f : X -> Y) : (forall y, exists x, f x = y) -> finite_t X -> finite_t Y.
proof: Proof. intros H (l & Hl). exists (map f l). intros y. destruct (H y) as (x & <-). apply in_map_iff; exists x; auto. Qed.
imports: List Arith Lia Eqdep_dec Bool Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list utils_nat) Undecidability.Shared.Libs.DLW.Vec(pos vec)