∀ {σ : Type u_1} {R : Type u_2} [inst : TopologicalSpace R] [inst_1 : Semiring R] {ι : Type u_3}
  (f : ι → MvPowerSeries σ R) (u : Filter ι) (g : MvPowerSeries σ R),
  Filter.Tendsto f u (nhds g) =
    ∀ (d : σ →₀ ℕ), Filter.Tendsto (fun i => (MvPowerSeries.coeff d) (f i)) u (nhds ((MvPowerSeries.coeff d) g))