∀ (C : Type u) [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Abelian C]
  [inst_2 : HasDerivedCategory C],
  DerivedCategory.singleFunctorsPostcompQIso C =
    (CategoryTheory.SingleFunctors.postcompFunctor C ℤ DerivedCategory.Qh).mapIso
        (HomotopyCategory.singleFunctorsPostcompQuotientIso C) ≪≫
      (CochainComplex.singleFunctors C).postcompPostcompIso (HomotopyCategory.quotient C (ComplexShape.up ℤ))
          DerivedCategory.Qh ≪≫
        (CochainComplex.singleFunctors C).postcompIsoOfIso (DerivedCategory.quotientCompQhIso C)