Module 1:Concepts of Random walks, Markov Chains, Markov Processes
  Lecture 2:Random Walks
 

Lemma 1.1 (b)

(b) If  and , then

Proof of Lemma 1.1 (b)

Since  for , hence the case of  is obvious. In case , then by our hypothesis  for , hence  for . Now as  is a monotone increasing function in , hence it has a finite limit which will be equal to . Here remember we utilize the result proved from (a).