∀ {ι : Type u_1} {ι' : Type u_4} {c : ComplexShape ι} {c' : ComplexShape ι'} {C : Type u_3}
  [inst : CategoryTheory.Category.{u_2, u_3} C] [inst_1 : CategoryTheory.Limits.HasZeroMorphisms C]
  (K : HomologicalComplex C c') (e : c.Embedding c') [inst_2 : e.IsTruncGE] [inst_3 : ∀ (i' : ι'), K.HasHomology i']
  (x x_1 : ι),
  ¬c.Rel x x_1 →
    (if hij : c.Rel x x_1 then
        if hi : e.BoundaryGE x then
          CategoryTheory.CategoryStruct.comp (HomologicalComplex.truncGE'.XIsoOpcycles K e hi).hom
            (CategoryTheory.CategoryStruct.comp (K.fromOpcycles (e.f x) (e.f x_1))
              (HomologicalComplex.truncGE'.XIso K e ⋯).inv)
        else
          CategoryTheory.CategoryStruct.comp (HomologicalComplex.truncGE'.XIso K e hi).hom
            (CategoryTheory.CategoryStruct.comp (K.d (e.f x) (e.f x_1)) (HomologicalComplex.truncGE'.XIso K e ⋯).inv)
      else 0) =
      0