Abstract :
Shows that for any sequence ρ(n)=o(n) and any sequence of prefix codes, there is a B-process of entropy arbitrarily close to the maximum possible entropy for which the expected redundancy is at least as large as ρ(n) for infinitely many n. This extends earlier work of the first author, whose examples had 0 entropy, [Shields, 1993]. The class of B-processes, that is, stationary codings of i.i.d. processes, includes the aperiodic Markov chains and functions thereof, aperiodic renewal and regenerative processes, and independent processes, as well as many other processes of interest. In particular, the results show that the search for a universal redundancy-rate for the class of all B-processes is doomed to failure, and redundancy rates for any given subclass must be obtained by direct analysis of that subclass
Keywords :
Markov processes; entropy codes; redundancy; sequences; B-processes; aperiodic Markov chains; aperiodic regenerative process; aperiodic renewal processes; entropy; iid processes; independent identically distributed processes; independent processes; prefix codes; sequence; stationary codings; subclass; universal redundancy rates; Entropy; Failure analysis; Polynomials;