∀ {I : Type u_1} [inst : DecidableEq I] (R : Type u_2) [inst_1 : CommSemiring R] (A : I → Type u_3)
  [inst_2 : (i : I) → Semiring (A i)] [inst_3 : (i : I) → Algebra R (A i)] (i : I) (x1 x2 : A i),
  (LinearAlgebra.FreeProduct.ι' R A) ((DirectSum.lof R I A i) (x1 * x2)) =
    (LinearAlgebra.FreeProduct.ι' R A) ((DirectSum.lof R I A i) x1) *
      (LinearAlgebra.FreeProduct.ι' R A) ((DirectSum.lof R I A i) x2)