4. (Reflected random walk) Let {Xn|n ≥ 0} be as in Q6. Show that
Xn+1 = X0 + Zn+1 − Xn m=0 min{0, Xm + Vm+1 − Um+1}, where Zn = Xn
m=1 (Vm − Um), n ≥ 1. Q5. (Extreme value process) Let {In|n ≥ 0} be
an i.i.d. sequence of Z-valued random variables such that P{I1 = k}
= pk, k ∈ Z and pk > 0 for some k > 0. Define Xn = max{I1,
I2, ·...