proposition: Lemma Forall_cancel : forall T A, inhabited T -> (∀t : T, A) ≈ A.
proof: Proof. intros T A [] π; split; intro; dec π; find; ok. Qed.
imports: RelationClasses Morphisms ClassicalRealizability.ShallowEmbedding ClassicalRealizability.Tactics ClassicalRealizability.BasicResults