proposition: Fact hfs_pair_pow r s t : r ∈ t -> s ∈ t -> hfs_pair r s ∈ hfs_pow t.
proof: Proof. rewrite hfs_pow_spec. intros H1 H2 x. rewrite hfs_pair_spec. intros [ -> | -> ]; auto. Qed.
imports: List Arith Lia Max Wellfounded Setoid Eqdep_dec Bool Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list finite) Undecidability.Shared.Libs.DLW.Vec(pos vec) Undecidability.Shared.Libs.DLW.Wf(wf_finite wf_chains) Undecidability.FOL.TRAKHTENBROT(notations fol_ops membership btree)