∀ {C : Type u_4} [inst : CategoryTheory.Category.{u_3, u_4} C] [inst_1 : CategoryTheory.MonoidalCategory C]
  {D : Type u_2} [inst_2 : CategoryTheory.Category.{u_1, u_2} D] [inst_3 : CategoryTheory.MonoidalCategory D]
  {F : CategoryTheory.Functor C D}
  (η : F.obj (CategoryTheory.MonoidalCategoryStruct.tensorUnit C) ⟶ CategoryTheory.MonoidalCategoryStruct.tensorUnit D)
  (δ : CategoryTheory.MonoidalCategory.curriedTensorPost F ⟶ CategoryTheory.MonoidalCategory.curriedTensorPre F),
  CategoryTheory.Functor.OplaxMonoidal.ofBifunctor.leftMapₗ F =
      CategoryTheory.CategoryStruct.comp (CategoryTheory.Functor.OplaxMonoidal.ofBifunctor.topMapₗ F)
        (CategoryTheory.CategoryStruct.comp (δ.app (CategoryTheory.MonoidalCategoryStruct.tensorUnit C))
          (CategoryTheory.Functor.OplaxMonoidal.ofBifunctor.bottomMapₗ η)) →
    ∀ (X : C),
      (CategoryTheory.Functor.OplaxMonoidal.ofBifunctor.leftMapₗ F).app X =
        (CategoryTheory.CategoryStruct.comp (CategoryTheory.Functor.OplaxMonoidal.ofBifunctor.topMapₗ F)
              (CategoryTheory.CategoryStruct.comp (δ.app (CategoryTheory.MonoidalCategoryStruct.tensorUnit C))
                (CategoryTheory.Functor.OplaxMonoidal.ofBifunctor.bottomMapₗ η))).app
          X