(C : Type u) →
  [inst : CategoryTheory.Category.{v, u} C] →
    [inst_1 : CategoryTheory.Preadditive C] →
      [inst_2 : CategoryTheory.Limits.HasZeroObject C] →
        HomotopyCategory.singleFunctors C ≅
          (CochainComplex.singleFunctors C).postcomp (HomotopyCategory.quotient C (ComplexShape.up ℤ))