Mutual information of several random variables and its estimation via variation

We obtain some upper and lower bounds for the maximum of mutual information of several random variables via variational distance between the joint distribution of these random variables and the product of its marginal distributions. In this connection, some properties of variational distance between probability distributions of this type are derived. We show that in some special cases estimates of the maximum of mutual information obtained here are optimal or asymptotically optimal. Some results of this paper generalize the corresponding results of [1–3] to the multivariate case.