proposition: Lemma prop_ext_A_eq_A_imp_A : prop_extensionality -> forall A:Prop, inhabited A -> (A -> A) = A.
proof: Proof. intros Ext A a. apply (Ext (A -> A) A); split; [ exact (fun _ => a) | exact (fun _ _ => a) ]. Qed.
imports: PropExtensionalityFacts