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In this study, we analytically characterize the conditions under which multi-letter extended AH coding improves upon SW coding. Our condition is tight in the sense that it coincides with the complement of the known SW optimal sufficient condition. To obtain the conditions, we apply the method of types to reduce the evaluation of the multi-letter expression to a comparison of single-letter divergences, which might be of independent interest.
From: Yohsuke Tsujino [view email]
[v1]
Wed, 24 Jun 2026 08:45:09 UTC (116 KB)
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