theorem variance_implies_margin_floor {sigma0_sq T Tstar V_target : ℝ}
(_hs : 0 < sigma0_sq) (hTs : 0 < Tstar) (hTlt : T < Tstar)
(hV : 0 < V_target)
(hvar : varianceAtFriction sigma0_sq T Tstar ≤ V_target) :
marginFloor sigma0_sq V_target ≤ 1 - T / Tstar := by
simp only [marginFloor, varianceAtFriction] at *
have hm : 0 < 1 - T / Tstar := by
rw [sub_pos, div_lt_one hTs]; exact hTlt
rw [div_le_iff₀ hV]
rw [div_le_iff₀ hm] at hvar
linarith [mul_comm V_target (1 - T / Tstar)]Variance Targeting Escapes Damping Cancellation