theorem universality {J₁ J₂ : ℕ} {ρ₁ ρ₂ : ℝ}
{T₁ Tstar₁ T₂ Tstar₂ : ℝ}
(hK1 : curvatureK J₁ ρ₁ ≠ 0)
(hK2 : curvatureK J₂ ρ₂ ≠ 0)
(hratio : T₁ / Tstar₁ = T₂ / Tstar₂) :
effectiveCurvatureKeff J₁ ρ₁ T₁ Tstar₁ / curvatureK J₁ ρ₁ =
effectiveCurvatureKeff J₂ ρ₂ T₂ Tstar₂ / curvatureK J₂ ρ₂ := by
rw [keff_reduced_universal J₁ ρ₁ T₁ Tstar₁ hK1,
keff_reduced_universal J₂ ρ₂ T₂ Tstar₂ hK2]
unfold reducedOrderParam
rw [hratio]Phase Transition at T* (Gap #8)