∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Preadditive C] {X Y : C}
  {f : X ⟶ Y} [inst_2 : CategoryTheory.IsSplitEpi f] {c : CategoryTheory.Limits.KernelFork f},
  CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.Fork.ι c)
      (CategoryTheory.CategoryStruct.id X -
        (CategoryTheory.CategoryStruct.id X - CategoryTheory.CategoryStruct.comp f (CategoryTheory.section_ f))) =
    0