∀ {ι : Type u_1} {V : Type u} [inst : CategoryTheory.Category.{v, u} V]
  [inst_1 : CategoryTheory.Limits.HasZeroMorphisms V] {c : ComplexShape ι} (C : HomologicalComplex V c) {i j : ι}
  (r : c.Rel i j), C.dFrom i = CategoryTheory.CategoryStruct.comp (C.d i j) (C.xNextIso r).inv