∀ {ι : Type u_2} (A : ι → Type u_1) [inst : Add ι] [inst_1 : (i : ι) → AddCommMonoid (A i)]
  [inst_2 : DirectSum.GNonUnitalNonAssocSemiring A] {i j : ι} (b c : A j),
  GradedMonoid.GMul.mul 0 (b + c) = GradedMonoid.GMul.mul 0 b + GradedMonoid.GMul.mul 0 c