proposition: Lemma hfs_listing_spec x y : y el hfs_listing x <-> hfs_mem y x.
proof: Proof. unfold hfs_listing. now destruct hfs_mem_fin_t. Qed.
imports: Undecidability.FOL(Syntax.Facts Semantics.Tarski.FullFacts) Undecidability.FOL(Sets.ZF) Undecidability.FOL(ZF) Undecidability.FOL.TRAKHTENBROT(hfs) Undecidability.Shared.Libs.DLW.Utils(finite) Undecidability(Shared.ListAutomation) Lia