proposition: Lemma surjective_tripleF (p : obj[F ↓ Id[C]]) : ((fst `1 p, snd `1 p); `2 p) = p.
proof: Proof. destruct p; simpl; simpl_eq. destruct x; reflexivity. Qed.
imports: Category.Lib Category.Theory.Category Category.Theory.Isomorphism Category.Theory.Functor Category.Theory.Natural.Transformation Category.Theory.Adjunction Category.Adjunction.Natural.Transformation Category.Adjunction.Natural.Transformation.Universal Category.Construction.Comma Category.Construction.Product Category.Instance.Cat Category.Instance.Fun Category.Instance.Sets