Spectral deviation of concentration operators on reproducing kernel Hilbert spaces

Fuente: arXiv
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Main Authors: Marceca, Felipe, Romero, José Luis, Speckbacher, Michael, Valentini, Lisa
Format: Preprint
Published: 2026
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author Marceca, Felipe
Romero, José Luis
Speckbacher, Michael
Valentini, Lisa
author_facet Marceca, Felipe
Romero, José Luis
Speckbacher, Michael
Valentini, Lisa
contents We study the eigenvalue profile of concentration operators (multiplication by an indicator function followed by projection) acting on reproducing kernel Hilbert spaces. The spectral profile of such operators provides a useful notion of local degrees of freedom. We formalize this idea by estimating the number of eigenvalues that lie away from 0 and 1, commonly referred to as the plunge region. Our main motivation is to treat discrete and continuous settings simultaneously and uniformly, and to be able to argue that approximations arising from discretization schemes reflect, in a non-asymptotic sense, the spectral profile of their continuous counterparts. As a case in point, we show that Gabor multipliers computed on sufficiently fine grids obey spectral deviation estimates similar to those available for the short-time Fourier transform (STFT) with bounds that are uniform in the discretization step. Concretely, this means that the theoretical localization properties of the STFT are observable in practice.
format Preprint
id arxiv_https___arxiv_org_abs_2603_10813
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spectral deviation of concentration operators on reproducing kernel Hilbert spaces
Marceca, Felipe
Romero, José Luis
Speckbacher, Michael
Valentini, Lisa
Spectral Theory
47B32, 47B35, 42C40, 47A75, 46E22
We study the eigenvalue profile of concentration operators (multiplication by an indicator function followed by projection) acting on reproducing kernel Hilbert spaces. The spectral profile of such operators provides a useful notion of local degrees of freedom. We formalize this idea by estimating the number of eigenvalues that lie away from 0 and 1, commonly referred to as the plunge region. Our main motivation is to treat discrete and continuous settings simultaneously and uniformly, and to be able to argue that approximations arising from discretization schemes reflect, in a non-asymptotic sense, the spectral profile of their continuous counterparts. As a case in point, we show that Gabor multipliers computed on sufficiently fine grids obey spectral deviation estimates similar to those available for the short-time Fourier transform (STFT) with bounds that are uniform in the discretization step. Concretely, this means that the theoretical localization properties of the STFT are observable in practice.
title Spectral deviation of concentration operators on reproducing kernel Hilbert spaces
topic Spectral Theory
47B32, 47B35, 42C40, 47A75, 46E22
url https://arxiv.org/abs/2603.10813