proposition: Fact fol_def_iff R T : fol_definable ls lr M R -> fol_definable ls lr M T -> fol_definable ls lr M (fun φ => R φ <-> T φ).
proof: Proof. intros; fol def. Qed.
imports: List Arith Lia Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list finite) Undecidability.Shared.Libs.DLW.Vec(pos vec) Undecidability.FOL.TRAKHTENBROT(notations utils fol_ops fo_sig fo_terms fo_logic)