∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Limits.HasZeroMorphisms C]
  {X Y : C} (f : X ⟶ Y) [inst_2 : CategoryTheory.Limits.HasKernel f],
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.kernel.ι f) f =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.kernel.ι f) 0