∀ {C : Type u_4} [inst : CategoryTheory.Category.{u_2, u_4} C] {D : Type u_3}
  [inst_1 : CategoryTheory.Category.{u_1, u_3} D] {R : CategoryTheory.Functor D C}
  [inst_2 : CategoryTheory.Coreflective R],
  (CategoryTheory.Comonad.comparison (CategoryTheory.coreflectorAdjunction R)).IsEquivalence