Problem:
Let (Xn) be a martingale and write ∆n = Xn - Xn-1, Suppose that bm ↑ ∞ and Σ∞m=1 b -2m E∆2m < ∞. Prove that Xn/bn → 0 a.s.
Additional Information:
This problem is basically from Mathematics and it is about martingale calculation
Note: The solution is in handwritten format.