proposition: Fact mb_is_pair_comm p x y : p ≋ ⦃x,y⦄ -> p ≋ ⦃y,x⦄.
proof: Proof. unfold mb_is_pair; fol equiv fa; intro; tauto. Qed.
imports: List Arith Nat Lia Max Wellfounded Coq.Setoids.Setoid Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list finite) Undecidability.Shared.Libs.DLW.Vec(pos vec) Undecidability.FOL.TRAKHTENBROT(notations fol_ops fo_sig fo_terms fo_logic)