∀ {R : Type u_3} [inst : CommRing R] {A : Type u_1} [inst_1 : CommRing A] {L : Type u_2} [inst_2 : Field L]
  [inst_3 : Algebra R A] [inst_4 : Algebra R L] {g : A →ₐ[R] L},
  Function.Injective ⇑g → ∀ (y : ↥(nonZeroDivisors A)), IsUnit (g.toRingHom ↑y)