∀ {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}
  (i : CategoryTheory.Limits.IsLimit c),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.section_ f)
      (let c' := CategoryTheory.Limits.KernelFork.ofι (CategoryTheory.Limits.Fork.ι c) ⋯;
      let i' := CategoryTheory.Limits.isKernelCompMono i (CategoryTheory.section_ f) ⋯;
      let i'' := CategoryTheory.Preadditive.isLimitForkOfKernelFork i';
      (CategoryTheory.Limits.splitMonoOfIdempotentOfIsLimitFork C ⋯ i'').retraction) =
    0