A Markov chain is said to be a tree process if (i) P>0 whenever P > 0.

(ii) for every pair of states i and j, ij, there is a unique sequence of distinct states iio, P>0, - j such that k = 0, 1,...,n-1 In other words, a Markov chain is a tree process if for every pair of distinct states and there is a unique way for the process to go from i to jwithout reentering a state (and this path is the reverse of the unique path from to i). Argue that an ergodic tree process is time reversible.