3.5.8 As a special case, consider a discrete-time queueing model in which at most a single customer arrives in any period and at most a single customer completes service. Suppose that in any single period, a single customer arrives with probability

, and no customers arrive with probability 1????. Provided that there are customers in the system, in a single period a single customer completes service with probability , and no customers leave with probability 1????. Then Xn, the number of customers in the system at the end-of-period n, is a random walk in the sense of Section 3.5.3. Referring to equation (3.38), specify the transition probabilities pi;qi, and ri for i D 0;1; : : : .