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arXiv 2005.10823cs.ITmath.IT
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带边信息的无损压缩的二阶点态渐近性

Sharp Second-Order Pointwise Asymptotics for Lossless Compression with Side Information

Lampros Gavalakis, Ioannis Kontoyiannis

摘要:

当相关边信息在编码器和解码器都可用时,确定任意无损压缩算法的最佳可实现性能的问题被检查。对于任意的源端信息对,条件信息密度示出为任意序列的压缩器实现的描述长度提供了一个尖锐的渐近下界。这意味着,对于遍历的源端信息对,条件熵率是该速率的最佳可实现的渐近下界,不仅在期望中,而且概率为1。在适当的混合条件下,证明了中心极限定理和重对数律,描述了二阶渐近最佳可能速率的不可避免的波动。一个理想化的版本Lempel-Ziv编码与边信息是普遍的第一和第二阶渐近最优,在相同的条件下。这些结果的一部分是基于一个新的几乎肯定的不变性原则的条件信息密度,这可能是独立的利益。

英文摘要:

The problem of determining the best achievable performance of arbitrary lossless compression algorithms is examined, when correlated side information is available at both the encoder and decoder. For arbitrary source-side information pairs, the conditional information density is shown to provide a sharp asymptotic lower bound for the description lengths achieved by an arbitrary sequence of compressors. This implies that, for ergodic source-side information pairs, the conditional entropy rate is the best achievable asymptotic lower bound to the rate, not just in expectation but with probability one. Under appropriate mixing conditions, a central limit theorem and a law of the iterated logarithm are proved, describing the inevitable fluctuations of the second-order asymptotically best possible rate. An idealised version of Lempel-Ziv coding with side information is shown to be universally first- and second-order asymptotically optimal, under the same conditions. These results are in part based on a new almost-sure invariance principle for the conditional information density, which may be of independent interest.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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