On spectral outliers of inhomogeneous symmetric random matrices

Fuente: arXiv
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Main Authors: Altschuler, Dylan J., Santos, Patrick Oliveira, Tikhomirov, Konstantin, Youssef, Pierre
Format: Preprint
Published: 2024
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author Altschuler, Dylan J.
Santos, Patrick Oliveira
Tikhomirov, Konstantin
Youssef, Pierre
author_facet Altschuler, Dylan J.
Santos, Patrick Oliveira
Tikhomirov, Konstantin
Youssef, Pierre
contents Sharp conditions for the presence of spectral outliers are well understood for Wigner random matrices with iid entries. In the setting of inhomogeneous symmetric random matrices (i.e., matrices with a non-trivial variance profile), the corresponding problem has been considered only recently. Of special interest is the setting of sparse inhomogeneous matrices since sparsity is both a key feature and a technical obstacle in various aspects of random matrix theory. For such matrices, the largest of the variances of the entries has been used in the literature as a natural proxy for sparsity. We contribute sharp conditions in terms of this parameter for an inhomogeneous symmetric matrix with sub-Gaussian entries to have outliers. Our result implies a ``structural'' universality principle: the presence of outliers is only determined by the level of sparsity, rather than the detailed structure of the variance profile.
format Preprint
id arxiv_https___arxiv_org_abs_2401_07852
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On spectral outliers of inhomogeneous symmetric random matrices
Altschuler, Dylan J.
Santos, Patrick Oliveira
Tikhomirov, Konstantin
Youssef, Pierre
Probability
Sharp conditions for the presence of spectral outliers are well understood for Wigner random matrices with iid entries. In the setting of inhomogeneous symmetric random matrices (i.e., matrices with a non-trivial variance profile), the corresponding problem has been considered only recently. Of special interest is the setting of sparse inhomogeneous matrices since sparsity is both a key feature and a technical obstacle in various aspects of random matrix theory. For such matrices, the largest of the variances of the entries has been used in the literature as a natural proxy for sparsity. We contribute sharp conditions in terms of this parameter for an inhomogeneous symmetric matrix with sub-Gaussian entries to have outliers. Our result implies a ``structural'' universality principle: the presence of outliers is only determined by the level of sparsity, rather than the detailed structure of the variance profile.
title On spectral outliers of inhomogeneous symmetric random matrices
topic Probability
url https://arxiv.org/abs/2401.07852