Concentration Inequalities for Sample Cross-Covariances

Fuente: arXiv
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Hauptverfasser: Chen, Jiaheng, Sanz-Alonso, Daniel
Format: Preprint
Veröffentlicht: 2026
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author Chen, Jiaheng
Sanz-Alonso, Daniel
author_facet Chen, Jiaheng
Sanz-Alonso, Daniel
contents This paper establishes sharp dimension-free concentration and expectation bounds for the deviation of a sample cross-covariance matrix from its mean. For sub-Gaussian random vectors, we prove a high-probability operator-norm bound governed by the effective ranks of the two marginal covariance matrices. In the Gaussian case, we prove a matching expectation lower bound, allowing arbitrary correlation between the two random vectors.
format Preprint
id arxiv_https___arxiv_org_abs_2605_16733
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Concentration Inequalities for Sample Cross-Covariances
Chen, Jiaheng
Sanz-Alonso, Daniel
Probability
Statistics Theory
This paper establishes sharp dimension-free concentration and expectation bounds for the deviation of a sample cross-covariance matrix from its mean. For sub-Gaussian random vectors, we prove a high-probability operator-norm bound governed by the effective ranks of the two marginal covariance matrices. In the Gaussian case, we prove a matching expectation lower bound, allowing arbitrary correlation between the two random vectors.
title Concentration Inequalities for Sample Cross-Covariances
topic Probability
Statistics Theory
url https://arxiv.org/abs/2605.16733