Matrix Chaos Inequalities and Chaos of Combinatorial Type


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Date

2025-06

Publication Type

Conference Paper

ETH Bibliography

yes

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Abstract

Matrix concentration inequalities and their recently discovered sharp counterparts provide powerful tools to bound the spectrum of random matrices whose entries are linear functions of independent random variables. However, in many applications in theoretical computer science and in other areas one encounters more general random matrix models, called matrix chaoses, whose entries are polynomials of independent random variables. Such models have often been studied on a case-by-case basis using ad-hoc methods that can yield suboptimal dimensional factors. In this paper we provide general matrix concentration inequalities for matrix chaoses, which enable the treatment of such models in a systematic manner. These inequalities are expressed in terms of flattenings of the coefficients of the matrix chaos. We further identify a special family of matrix chaoses of combinatorial type for which the flattening parameters can be computed mechanically by a simple rule. This allows us to provide a unified treatment of and improved bounds for matrix chaoses that arise in a variety of applications, including graph matrices, Khatri-Rao matrices, and matrices that arise in average case analysis of the sum-of-squares hierarchy.

Publication status

published

Book title

STOC '25: Proceedings of the 57th Annual ACM Symposium on Theory of Computing

Journal / series

Volume

Pages / Article No.

795 - 805

Publisher

Association for Computing Machinery

Event

57th Annual ACM Symposium on Theory of Computing (STOC 2025)

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Random matrices; matrix concentration inequalities

Organisational unit

09679 - Bandeira, Afonso / Bandeira, Afonso check_circle

Notes

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