Avoiding spectral pollution for transfer operators using residuals

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Herwig, April, Colbrook, Matthew J., Junge, Oliver, Koltai, Péter, Slipantschuk, Julia
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911071943524352
author Herwig, April
Colbrook, Matthew J.
Junge, Oliver
Koltai, Péter
Slipantschuk, Julia
author_facet Herwig, April
Colbrook, Matthew J.
Junge, Oliver
Koltai, Péter
Slipantschuk, Julia
contents Koopman operator theory enables linear analysis of nonlinear dynamical systems by lifting their evolution to infinite-dimensional function spaces. However, finite-dimensional approximations of Koopman and transfer (Frobenius--Perron) operators are prone to spectral pollution, introducing spurious eigenvalues that can compromise spectral computations. While recent advances have yielded provably convergent methods for Koopman operators, analogous tools for general transfer operators remain limited. In this paper, we present algorithms for computing spectral properties of transfer operators without spectral pollution, including extensions to the Hardy-Hilbert space. Case studies--ranging from families of Blaschke maps with known spectrum to a molecular dynamics model of protein folding--demonstrate the accuracy and flexibility of our approach. Notably, we demonstrate that spectral features can arise even when the corresponding eigenfunctions lie outside the chosen space, highlighting the functional-analytic subtleties in defining the "true" Koopman spectrum. Our methods offer robust tools for spectral estimation across a broad range of applications.
format Preprint
id arxiv_https___arxiv_org_abs_2507_16915
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Avoiding spectral pollution for transfer operators using residuals
Herwig, April
Colbrook, Matthew J.
Junge, Oliver
Koltai, Péter
Slipantschuk, Julia
Dynamical Systems
Machine Learning
Numerical Analysis
Spectral Theory
Koopman operator theory enables linear analysis of nonlinear dynamical systems by lifting their evolution to infinite-dimensional function spaces. However, finite-dimensional approximations of Koopman and transfer (Frobenius--Perron) operators are prone to spectral pollution, introducing spurious eigenvalues that can compromise spectral computations. While recent advances have yielded provably convergent methods for Koopman operators, analogous tools for general transfer operators remain limited. In this paper, we present algorithms for computing spectral properties of transfer operators without spectral pollution, including extensions to the Hardy-Hilbert space. Case studies--ranging from families of Blaschke maps with known spectrum to a molecular dynamics model of protein folding--demonstrate the accuracy and flexibility of our approach. Notably, we demonstrate that spectral features can arise even when the corresponding eigenfunctions lie outside the chosen space, highlighting the functional-analytic subtleties in defining the "true" Koopman spectrum. Our methods offer robust tools for spectral estimation across a broad range of applications.
title Avoiding spectral pollution for transfer operators using residuals
topic Dynamical Systems
Machine Learning
Numerical Analysis
Spectral Theory
url https://arxiv.org/abs/2507.16915