Umlaut information

Fuente: arXiv
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Bibliographic Details
Main Authors: Girardi, Filippo, Oufkir, Aadil, Regula, Bartosz, Tomamichel, Marco, Berta, Mario, Lami, Ludovico
Format: Preprint
Published: 2025
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author Girardi, Filippo
Oufkir, Aadil
Regula, Bartosz
Tomamichel, Marco
Berta, Mario
Lami, Ludovico
author_facet Girardi, Filippo
Oufkir, Aadil
Regula, Bartosz
Tomamichel, Marco
Berta, Mario
Lami, Ludovico
contents The sphere-packing bound quantifies the error exponent for noisy channel coding for rates above a critical value. Here, we study the zero-rate limit of the sphere-packing bound and show that it has an intriguing single-letter form, which we call the umlaut information of the channel, inspired by the lautum information introduced by Palomar and Verdú. Unlike the latter quantity, we show that the umlaut information is additive for parallel uses of channels. We show that it has a twofold operational interpretation: as the zero-rate error exponent of non-signalling-assisted coding on the one hand, and as the zero-rate error exponent of list decoding in the large list limit on the other.
format Preprint
id arxiv_https___arxiv_org_abs_2503_18910
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Umlaut information
Girardi, Filippo
Oufkir, Aadil
Regula, Bartosz
Tomamichel, Marco
Berta, Mario
Lami, Ludovico
Information Theory
Mathematical Physics
Quantum Physics
The sphere-packing bound quantifies the error exponent for noisy channel coding for rates above a critical value. Here, we study the zero-rate limit of the sphere-packing bound and show that it has an intriguing single-letter form, which we call the umlaut information of the channel, inspired by the lautum information introduced by Palomar and Verdú. Unlike the latter quantity, we show that the umlaut information is additive for parallel uses of channels. We show that it has a twofold operational interpretation: as the zero-rate error exponent of non-signalling-assisted coding on the one hand, and as the zero-rate error exponent of list decoding in the large list limit on the other.
title Umlaut information
topic Information Theory
Mathematical Physics
Quantum Physics
url https://arxiv.org/abs/2503.18910