theorem variance_monotone {sigma0_sq T₁ T₂ Tstar : ℝ}
(hsigma : 0 < sigma0_sq) (hTs : 0 < Tstar)
(_hT1 : T₁ < Tstar) (_hT2 : T₂ < Tstar) (h12 : T₁ ≤ T₂) :
varianceAtFriction sigma0_sq T₁ Tstar ≤
varianceAtFriction sigma0_sq T₂ Tstar := by
simp only [varianceAtFriction]
apply div_le_div_of_nonneg_left (le_of_lt hsigma)
· rw [sub_pos, div_lt_one hTs]; linarith
· apply sub_le_sub_left
exact div_le_div_of_nonneg_right h12 (le_of_lt hTs)Results 8-16: Variance-Response Identity and Early Warning