theorem discountGap_sensitivity {γ g₀ β τ : ℝ} : discountGap (γ + g₀ * β) (γ + g₀ * β) τ = (γ + g₀ * β) * (1 + τ) := by simp only [discountGap]; ring
thesis/CESProofs/Macro/GrowthTax.lean:176
Growth and Dynamic Tax Revenue (Layer 4-5 of Macro Extension)