theorem lafferRevenue_at_peak {B₀ η : ℝ} (hη : η ≠ 0) :
lafferRevenue B₀ η (lafferPeak η) = lafferMaxRevenue B₀ η := by
simp only [lafferRevenue, lafferPeak, lafferMaxRevenue]; field_simp; ringGovernment Tax Structure (Layer 3 of Macro Extension)