proposition: Lemma create_extensionality : forall f g t f1 g1 t1, f = f1 -> g = g1 -> (forall x, inc x (objects (source f)) -> t x = t1 x) -> create f g t = create f1 g1 t1.
proof: Proof. ir. wr H; wr H0. uf create. ap uneq. uf ntrans_arrow_create. up. app Function.create_extensionality. ir. au. Qed.
imports: Arith functor