theorem npv_no_dynamic_equals_static {B₀ η D₀ τ : ℝ} : npvRevenue B₀ η D₀ 0 τ = lafferRevenue B₀ η τ / D₀ := by simp only [npvRevenue, discountGap]; ring
thesis/CESProofs/Macro/GrowthTax.lean:247
Growth and Dynamic Tax Revenue (Layer 4-5 of Macro Extension)