IfXare iid.rvs with EX, &>, then ET, there is an integer n such that PiS,

c) 0.

Prove that if is possible and bis recurrent, then be is recurrent. Since every recurrent value is clearly possible, the set Q of recurrent values is an additive group. Show that Qis closed. Thus, if is nonempty, Q-(-, x) or (ne: +2 or Q (01 (the latter only if X is degenerate at 001.