proposition: Theorem reflect_iff : forall P b, reflect P b -> (P <-> b = true).
proof: Proof. Admitted. Lemma beq_natP : forall n m, reflect (n = m) (beq_nat n m). Proof. intros n m. apply iff_reflect. rewrite beq_nat_true_iff. reflexivity. Qed.
imports: Logic