∀ {σ : Type u_1} {R : Type u_2} [inst : Semiring R] [inst_1 : LinearOrder σ] [inst_2 : WellFoundedGT σ]
  {φ : MvPowerSeries σ R} {w : WithTop (Lex (σ →₀ ℕ))},
  w ≤ φ.lexOrder ↔ ∀ (d : σ →₀ ℕ), ↑(toLex d) < w → (MvPowerSeries.coeff d) φ = 0