∀ {ι : Type u_1} {σ : Type u_3} {R : Type u_2} [inst : AddCommMonoid ι] [inst_1 : CommRing R] [inst_2 : SetLike σ R]
  (A : ι → σ) [inst_3 : SetLike.GradedMonoid A] (a b c : GradedMonoid fun i => ↥(A i)), a * b * c = a * (b * c)