On an Application of Relative Entropy

We describe general approach to classification of character sequences (texts, DNA) using relative entropy estimated by off-the-shelf compression and Markov Chains and find them precise enough. We also notice that the method for estimating relative entropy described in the paper cond-mat/0108530 "Language Trees..." by D. Benedetto et al. was considered earlier and was found to be easily surpassed by the simple and computationally effective first order Markov Chain approach.