theorem discountGap_increasing {D₀ δ_gap τ₁ τ₂ : ℝ}
(hδ : 0 < δ_gap) (hτ : τ₁ < τ₂) :
discountGap D₀ δ_gap τ₁ < discountGap D₀ δ_gap τ₂ := by
simp only [discountGap]
linarith [mul_lt_mul_of_pos_left hτ hδ]Growth and Dynamic Tax Revenue (Layer 4-5 of Macro Extension)