Greedy-Merge Degrading has Optimal Power-Law

Consider a channel with a given input distribution. Our aim is to degrade it to a channel with at most L output letters. One such degradation method is the so called "greedy-merge" algorithm. We derive an upper bound on the reduction in mutual information between input and output. For fixe...

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Bibliographic Details
Published inarXiv.org
Main Authors Assaf Kartowsky, Tal, Ido
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 06.05.2017
Subjects
Communication channels
Degradation
Greedy algorithms
Lower bounds
Power law
Upper bounds
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Summary:Consider a channel with a given input distribution. Our aim is to degrade it to a channel with at most L output letters. One such degradation method is the so called "greedy-merge" algorithm. We derive an upper bound on the reduction in mutual information between input and output. For fixed input alphabet size and variable L, the upper bound is within a constant factor of an algorithm-independent lower bound. Thus, we establish that greedy-merge is optimal in the power-law sense.
ISSN:2331-8422