∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] [inst_1 : CategoryTheory.CartesianMonoidalCategory C]
  (X : C),
  (CategoryTheory.toOverIsoToOverUnit.hom.app X).left =
    CategoryTheory.CategoryStruct.comp
      ((CategoryTheory.equivToOverUnit C).unit.app
          ((CategoryTheory.toOver (CategoryTheory.MonoidalCategoryStruct.tensorUnit C)).obj X)).left
      (CategoryTheory.SemiCartesianMonoidalCategory.fst X (CategoryTheory.MonoidalCategoryStruct.tensorUnit C))