proposition: Lemma hfs_no_loop x : ~ hfs_mem x x.
proof: Proof. induction (hfs_mem_wf x) as [x _ IH]. intros H. now apply (IH x). 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