On the submatrices with the best-bounded inverses

Fuente: arXiv
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Auteurs principaux: Sengupta, Richik, Pautov, Mikhail
Format: Preprint
Publié: 2026
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author Sengupta, Richik
Pautov, Mikhail
author_facet Sengupta, Richik
Pautov, Mikhail
contents The following hypothesis was formulated by Goreinov, Tyrtyshnikov, and Zamarashkin in \cite{goreinov1997theory}. If $U$ is $n\times k$ real matrix with the orthonormal columns $(n>k)$, then there exists a submatrix $Q$ of $U$ of size $k\times k$ such that its smallest singular value is at least $\frac{1}{\sqrt{n}}.$ Although this statement is supported by numerical experiments, the problem remains open for all $1<k<n-1,$ except for the case of $n = 4,\ k=2.$ In this work, we provide a proof for the case $k=2$ and arbitrary $n.$
format Preprint
id arxiv_https___arxiv_org_abs_2604_05944
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On the submatrices with the best-bounded inverses
Sengupta, Richik
Pautov, Mikhail
Numerical Analysis
The following hypothesis was formulated by Goreinov, Tyrtyshnikov, and Zamarashkin in \cite{goreinov1997theory}. If $U$ is $n\times k$ real matrix with the orthonormal columns $(n>k)$, then there exists a submatrix $Q$ of $U$ of size $k\times k$ such that its smallest singular value is at least $\frac{1}{\sqrt{n}}.$ Although this statement is supported by numerical experiments, the problem remains open for all $1<k<n-1,$ except for the case of $n = 4,\ k=2.$ In this work, we provide a proof for the case $k=2$ and arbitrary $n.$
title On the submatrices with the best-bounded inverses
topic Numerical Analysis
url https://arxiv.org/abs/2604.05944