∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Preadditive C]
  {F G : CochainComplex C ℤ} (z₁ z₂ : CochainComplex.HomComplex.Cochain F G 0),
  (∀ (p : ℤ), z₁.v p p ⋯ = z₂.v p p ⋯) → z₁ = z₂