∀ {σ : Type u_1} {R : Type u_3} [inst : CommRing R] {τ : Type u_4} {S : Type u_5} [inst_1 : CommRing S]
  [inst_2 : Algebra R S] {a : σ → MvPowerSeries τ S} (ha : MvPowerSeries.HasSubst a) (p : MvPolynomial σ R),
  (MvPowerSeries.substAlgHom ha) ↑p = (MvPolynomial.aeval a) p