theorem curvatureK_two_factor_pos {ρ : ℝ} (hρ : ρ < 1) : 0 < curvatureK 2 ρ := by rw [curvatureK_two_factor] linarith
thesis/CESProofs/Macro/TwoFactorCES.lean:343
Two-Factor CES Production Function (Layer 1 of Macro Extension)