proposition: Fact bt_opair_spec x s t : x ∈ ⟬s,t⟭ <-> x ≈ s⪧∅ \/ x ≈ s⪧t⪧∅.
proof: Proof. unfold bt_opair; btm simpl. 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)