Sharp Anti-Concentration Inequalities for Extremum Statistics via Copulas

Fuente: arXiv
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Auteurs principaux: Cattaneo, Matias D., Masini, Ricardo P., Underwood, William G.
Format: Preprint
Publié: 2025
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author Cattaneo, Matias D.
Masini, Ricardo P.
Underwood, William G.
author_facet Cattaneo, Matias D.
Masini, Ricardo P.
Underwood, William G.
contents We derive sharp upper and lower bounds for the pointwise concentration function of the maximum statistic of $d$ identically distributed real-valued random variables. Our first main result places no restrictions either on the common marginal law of the samples or on the copula describing their joint distribution. We show that, in general, strictly sublinear dependence of the concentration function on the dimension $d$ is not possible. We then introduce a new class of copulas, namely those with a convex diagonal section, and demonstrate that restricting to this class yields a sharper upper bound on the concentration function. This allows us to establish several new dimension-independent and poly-logarithmic-in-$d$ anti-concentration inequalities for a variety of marginal distributions under mild dependence assumptions. Our theory improves upon the best known results in certain special cases. Applications to high-dimensional statistical inference are presented, including a specific example pertaining to Gaussian mixture approximations for factor models, for which our main results lead to superior distributional guarantees.
format Preprint
id arxiv_https___arxiv_org_abs_2502_07699
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sharp Anti-Concentration Inequalities for Extremum Statistics via Copulas
Cattaneo, Matias D.
Masini, Ricardo P.
Underwood, William G.
Statistics Theory
Probability
60E15 (Primary) 62H05, 62G32 (Secondary)
We derive sharp upper and lower bounds for the pointwise concentration function of the maximum statistic of $d$ identically distributed real-valued random variables. Our first main result places no restrictions either on the common marginal law of the samples or on the copula describing their joint distribution. We show that, in general, strictly sublinear dependence of the concentration function on the dimension $d$ is not possible. We then introduce a new class of copulas, namely those with a convex diagonal section, and demonstrate that restricting to this class yields a sharper upper bound on the concentration function. This allows us to establish several new dimension-independent and poly-logarithmic-in-$d$ anti-concentration inequalities for a variety of marginal distributions under mild dependence assumptions. Our theory improves upon the best known results in certain special cases. Applications to high-dimensional statistical inference are presented, including a specific example pertaining to Gaussian mixture approximations for factor models, for which our main results lead to superior distributional guarantees.
title Sharp Anti-Concentration Inequalities for Extremum Statistics via Copulas
topic Statistics Theory
Probability
60E15 (Primary) 62H05, 62G32 (Secondary)
url https://arxiv.org/abs/2502.07699