proposition: Fact bti_congr_l x y t : x ≈ y -> x ⊆ t-> y ⊆ t.
proof: Proof. intros H1 H2 z Hz. apply H2; revert Hz; apply btm_congr_r; auto. Qed.
imports: List Arith Lia Max Wellfounded Setoid Eqdep_dec Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list utils_decidable finite seteq) Undecidability.Shared.Libs.DLW.Vec(pos) Undecidability.Shared.Libs.DLW.Wf(wf_finite wf_chains) Undecidability.FOL.TRAKHTENBROT(notations fol_ops)