{ι : Type u_1} →
  {A : ι → Type u_2} →
    [inst : Add ι] →
      {motive : GradedMonoid.GMul A → Sort u} →
        (t : GradedMonoid.GMul A) → ((mul : {i j : ι} → A i → A j → A (i + j)) → motive { mul := mul }) → motive t