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Least singular values of Gaussian matrices with deterministic shifts
Abstract
Let A be a deterministic real square matrix and G a standard Gaussian matrix. We determine Esmin(A+G), up to universal constants, in terms of the singular values of A. The expectation is comparable to the square root of the smallest zero of the expected characteristic polynomial of (A+G)⊤(A+G). This resolves Problem~3 in Tikhomirov's ICM 2022 survey. We also prove that the zeros of the expected characteristic polynomial are majorized by the expected ordered eigenvalues of (A+G)⊤(A+G).
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BibTeX
@misc{hu2026least,
title = {{Least singular values of Gaussian matrices with deterministic shifts}},
author = {Xuanang Hu and Zeyan Song and Xinglong Wu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.27008},
eprint = {2610.27008},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.27008},
}
RIS
TY - UNPB
TI - Least singular values of Gaussian matrices with deterministic shifts
AU - Xuanang Hu
AU - Zeyan Song
AU - Xinglong Wu
PY - 2026
DA - 2026/10/19
PB - arXiv
DO - 10.48550/arxiv.2610.27008
UR - https://arxiv.org/abs/2610.27008
AB - Let A be a deterministic real square matrix and G a standard Gaussian matrix. We determine Esmin(A+G), up to universal constants, in terms of the singular values of A. The expectation is comparable to the square root of the smallest zero of the expected characteristic polynomial of (A+G)^⊤(A+G). This resolves Problem~3 in Tikhomirov's ICM 2022 survey. We also prove that the zeros of the expected characteristic polynomial are majorized by the expected ordered eigenvalues of (A+G)^⊤(A+G).
ER -