Jack Huan Xie

Difficult I am not so sure about part (b) of the definition of martingale, why the expectation of future fortune is equal to Sn?  Is it beca...

Difficult In the proof of Theorem (4), I am not sure why "if Sn-S0=k, then r-s=k and r+s=n". Is k an arbitrary number? Also, in ...

Difficult In the proof of Theorem 6, I am not sure why we should assume "the sums are absolutely convergent".  We make that assump...

Difficult In the solution of example (9), I am not sure why the Chebyshov's Inequality is used to solved this problem. Is it possible t...

Difficult In the definition, I understand how the convergence is defined; and I tried to prove that, but I didn't succeed, so I am curio...

Difficult In section 3.6, I tried to do the proofs for Theorem 6 to Theorem 9.  I used the hint from the top of page 91, so I had no problem...

Difficult In the solution of the example, I can understand almost all the explanations.  However, I am not sure how the series come up for t...