theorem curvature_gain_increases_with_complementarity {ρ₁ ρ₂ : ℝ} {N : ℕ}
(hN : 2 ≤ N) (h : ρ₁ < ρ₂) :
concentrationWelfareCost ρ₂ N < concentrationWelfareCost ρ₁ N := by
simp only [concentrationWelfareCost]
apply mul_lt_mul_of_pos_right (by linarith)
have hNpos : (0 : ℝ) < ↑N := by exact_mod_cast (by omega : 0 < N)
have hNgt1 : (1 : ℝ) < ↑N := by exact_mod_cast (by omega : 1 < N)
have : 1 / (↑N : ℝ) < 1 := by rw [div_lt_one hNpos]; exact hNgt1
linarithFair Inheritance: Taxing Concentration, Not Transfer