, Volume 14, Issue 3, pp 186-227,
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Compression of Samplable Sources

Abstract.

We study the compression of polynomially samplable sources. In particular, we give efficient prefix-free compression and decompression algorithms for three classes of such sources (whose support is a subset of {0, 1} n ).

  1. We show how to compress sources X samplable by logspace machines to expected length H(X) + O(1).

Our next results concern flat sources whose support is in P.
  1. If H(X) ≤ k =  n − O(log n), we show how to compress to expected length k + polylog(nk).

  2. If the support of X is the witness set for a self-reducible NP relation, then we show how to compress to expected length H(X) + 5.

Manuscript received 31 December 2004