proposition: Fact hfs_pow_mono s t : s ⊆ t -> hfs_pow s ⊆ hfs_pow t.
proof: Proof. intros H x; do 2 rewrite hfs_pow_spec. intros G z Hz; apply H, G; 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)