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Universal coding of nonstationary sources

We investigate the performance of the Lempel-Ziv (1978) incremental parsing scheme on nonstationary sources. We show that it achieves the best rate achievable by a finite-state block coder for the nonstationary source. We also show a similar result for a lossy coding scheme given by Yang and Kieffer (see ibid., vol.42, p.239-45, 1996) which uses a Lempel-Ziv scheme to perform lossy coding.