theorem keff_reduced_universal (J : ℕ) (ρ T Tstar : ℝ)
(hK : curvatureK J ρ ≠ 0) :
effectiveCurvatureKeff J ρ T Tstar / curvatureK J ρ =
reducedOrderParam T Tstar := by
rw [keff_eq_K_times_reduced]
exact mul_div_cancel_left₀ _ hKPhase Transition at T* (Gap #8)