Let Y be a random variable independent of all the X j , with E |Y | <>∞. Let Uj := Y + Tj for j = -1, -2,... . Let Ck be the smallest σ-algebra for which Uj is measurable for all j ≤ k. Show that {Uk, Ck }k≤-1 is a reversed martingale and find its limit as k → -∞. Let C-∞ := nk≤-1 Ck . Is Y equal a.s. to a variable measurable for C-∞?