∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] [inst_1 : CategoryTheory.Abelian C]
  {R₁ R₂ : CategoryTheory.ComposableArrows C 2} (φ : R₁ ⟶ R₂),
  R₁.Exact →
    R₂.Exact →
      CategoryTheory.Epi
          (R₁.map' 1 2 CategoryTheory.Abelian.mono_of_epi_of_mono_of_mono'._proof_6
            CategoryTheory.Abelian.mono_of_epi_of_epi_mono'._proof_1) →
        CategoryTheory.Epi
            (CategoryTheory.ComposableArrows.app' φ 0 CategoryTheory.Abelian.mono_of_epi_of_mono_of_mono'._proof_2) →
          CategoryTheory.Mono
              (CategoryTheory.ComposableArrows.app' φ 1 CategoryTheory.Abelian.mono_of_epi_of_mono_of_mono'._proof_6) →
            CategoryTheory.Mono
              (CategoryTheory.ComposableArrows.app' φ 2 CategoryTheory.Abelian.mono_of_epi_of_epi_mono'._proof_1)