⇑f 0 1 : ℕ
f 0 1 : ℕ
⇑f 0 1 : ℕ
@coe_fn.{1 1} (Functor.{1} nat) (coe_functor_to_fn.{1} nat) f (@zero.{1} nat nat.has_zero) (@one.{1} nat nat.has_one) :
  nat