∀ {k G : Type u} [inst : CommRing k] [inst_1 : Group G] (A : Rep k G) (x : ↑(groupCohomology.cocycles A 0)),
  (CategoryTheory.ConcreteCategory.hom (groupCohomology.shortComplexH0 A).f)
      ((CategoryTheory.ConcreteCategory.hom (groupCohomology.cocyclesIso₀ A).hom) x) =
    (CategoryTheory.ConcreteCategory.hom (groupCohomology.cochainsIso₀ A).hom)
      ((CategoryTheory.ConcreteCategory.hom (groupCohomology.iCocycles A 0)) x)