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A Lower Bound on the Complexity of Approximating the Entropy of a Markov Source

2009/12/27 by Gagie, Travis
#FOS: Computer and information sciences #Information Theory (cs.IT)

paper · doi:10.48550/arxiv.0912.5079

Abstract

Suppose that, for any (k ≥ 1), (ε> 0) and sufficiently large σ, we are given a black box that allows us to sample characters from a kth-order Markov source over the alphabet (\0, ..., σ- 1\). Even if we know the source has entropy either 0 or at least (log (σ- k)), there is still no algorithm that, with probability bounded away from (1 / 2), guesses the entropy correctly after sampling at most ((σ- k)k / 2 - ε) characters.

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