Spectral equivalence of unsymmetric kernel matrices and applications

Fuente: arXiv
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Main Authors: Wenzel, Tizian, Iske, Armin
Format: Preprint
Published: 2025
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author Wenzel, Tizian
Iske, Armin
author_facet Wenzel, Tizian
Iske, Armin
contents Symmetric kernel matrices are a well-researched topic in the literature of kernel based approximation. In particular stability properties in terms of lower bounds on the smallest eigenvalue of such symmetric kernel matrices are thoroughly investigated, as they play a fundamental role in theory and practice. In this work, we focus on unsymmetric kernel matrices and derive stability properties under small shifts by establishing a spectral equivalence to their unshifted, symmetric versions. This extends and generalizes results for translational invariant kernels upon Quak et al [SIAM Journal on Math. Analysis, 1993] and Sivakumar and Ward [Numerische Mathematik, 1993], however focussing instead on finitely smooth kernels. As applications, we consider convolutional kernels over domains, which are no longer translational invariant, but which are still an important class of kernels for applications. For these, we derive novel lower bounds for the smallest eigenvalue of the kernel matrices in terms of the separation distance of the data points, and thus derive stability bounds in terms of the condition number.
format Preprint
id arxiv_https___arxiv_org_abs_2509_24561
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectral equivalence of unsymmetric kernel matrices and applications
Wenzel, Tizian
Iske, Armin
Numerical Analysis
Symmetric kernel matrices are a well-researched topic in the literature of kernel based approximation. In particular stability properties in terms of lower bounds on the smallest eigenvalue of such symmetric kernel matrices are thoroughly investigated, as they play a fundamental role in theory and practice. In this work, we focus on unsymmetric kernel matrices and derive stability properties under small shifts by establishing a spectral equivalence to their unshifted, symmetric versions. This extends and generalizes results for translational invariant kernels upon Quak et al [SIAM Journal on Math. Analysis, 1993] and Sivakumar and Ward [Numerische Mathematik, 1993], however focussing instead on finitely smooth kernels. As applications, we consider convolutional kernels over domains, which are no longer translational invariant, but which are still an important class of kernels for applications. For these, we derive novel lower bounds for the smallest eigenvalue of the kernel matrices in terms of the separation distance of the data points, and thus derive stability bounds in terms of the condition number.
title Spectral equivalence of unsymmetric kernel matrices and applications
topic Numerical Analysis
url https://arxiv.org/abs/2509.24561