Estimation of discrete distributions with high probability under $χ^2$-divergence

Fuente: arXiv
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Main Author: Louati, Sirine
Format: Preprint
Published: 2025
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author Louati, Sirine
author_facet Louati, Sirine
contents We investigate the high-probability estimation of discrete distributions from an \iid sample under $χ^2$-divergence loss. Although the minimax risk in expectation is well understood, its high-probability counterpart remains largely unexplored. We provide sharp upper and lower bounds for the classical Laplace estimator, showing that it achieves optimal performance among estimators that do not rely on the confidence level. We further characterize the minimax high-probability risk for any estimator and demonstrate that it can be attained through a simple smoothing strategy. Our analysis highlights an intrinsic separation between asymptotic and non-asymptotic guarantees, with the latter suffering from an unavoidable overhead. This work sharpens existing guarantees and advances the theoretical understanding of divergence-based estimation.
format Preprint
id arxiv_https___arxiv_org_abs_2510_25400
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Estimation of discrete distributions with high probability under $χ^2$-divergence
Louati, Sirine
Statistics Theory
Machine Learning
We investigate the high-probability estimation of discrete distributions from an \iid sample under $χ^2$-divergence loss. Although the minimax risk in expectation is well understood, its high-probability counterpart remains largely unexplored. We provide sharp upper and lower bounds for the classical Laplace estimator, showing that it achieves optimal performance among estimators that do not rely on the confidence level. We further characterize the minimax high-probability risk for any estimator and demonstrate that it can be attained through a simple smoothing strategy. Our analysis highlights an intrinsic separation between asymptotic and non-asymptotic guarantees, with the latter suffering from an unavoidable overhead. This work sharpens existing guarantees and advances the theoretical understanding of divergence-based estimation.
title Estimation of discrete distributions with high probability under $χ^2$-divergence
topic Statistics Theory
Machine Learning
url https://arxiv.org/abs/2510.25400