∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Limits.HasZeroMorphisms C]
  {X Y : C} {g : X ⟶ Y} {c : CategoryTheory.Limits.KernelFork g} {Y' : C} (g' : X ⟶ Y'),
  (∀ ⦃W : C⦄ (φ : W ⟶ X), CategoryTheory.CategoryStruct.comp φ g = 0 ↔ CategoryTheory.CategoryStruct.comp φ g' = 0) →
    CategoryTheory.CategoryStruct.comp (CategoryTheory.Limits.Fork.ι c) g' = 0