GENERALIZED CUTOFF RATES AND RENYIS INFORMATION MEASURES

Renyi's entropy and divergence of order alpha are given operational characterizations in terms of block coding and hypothesis testing, as so-called beta-cutoff rates, with alpha = (1 + beta)(-1) for entropy and alpha = (1 - beta)(-1) for divergence. Out of several possible definitions of mutual information and channel capacity of order alpha, our approach distinguishes one that admits an operational characterization as beta-cutoff rate for channel coding, with alpha = (1 - beta)(-1) The ordinary cutoff rate of a DMC corresponds to beta = -1.