proposition: Fact fo_term_subst_map f t : t⟬fun x => in_var (f x)⟭ = fo_term_map f t.
proof: Proof. induction t; rew fot; f_equal. apply vec_pos_ext; intro; rew vec. Qed.
imports: List Arith Lia Eqdep_dec Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list utils_nat finite) Undecidability.Shared.Libs.DLW.Vec(pos vec) Undecidability.FOL.TRAKHTENBROT(notations utils decidable fol_ops fo_sig)