∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {M : Type u_1} [inst_1 : CategoryTheory.Category.{v_1, u_1} M]
  [inst_2 : CategoryTheory.MonoidalCategory M] (F : CategoryTheory.Functor M (CategoryTheory.Functor C C))
  (m₁ m₂ m₃ : M) (X : C) [inst_3 : F.LaxMonoidal],
  CategoryTheory.CategoryStruct.comp ((F.obj m₃).map ((CategoryTheory.Functor.LaxMonoidal.μ F m₁ m₂).app X))
      (CategoryTheory.CategoryStruct.comp
        ((CategoryTheory.Functor.LaxMonoidal.μ F (CategoryTheory.MonoidalCategoryStruct.tensorObj m₁ m₂) m₃).app X)
        ((F.map (CategoryTheory.MonoidalCategoryStruct.associator m₁ m₂ m₃).hom).app X)) =
    CategoryTheory.CategoryStruct.comp ((CategoryTheory.Functor.LaxMonoidal.μ F m₂ m₃).app ((F.obj m₁).obj X))
      ((CategoryTheory.Functor.LaxMonoidal.μ F m₁ (CategoryTheory.MonoidalCategoryStruct.tensorObj m₂ m₃)).app X)