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Koopmans spectral functionals aim to describe simultaneously ground state properties and charged excitations of atoms, molecules, nanostructures and periodic crystals. This is achieved by augmenting standard density functionals with simple…

Materials Science · Physics 2022-07-25 Nicola Colonna , Riccardo De Gennaro , Edward Linscott , Nicola Marzari

Koopman operators linearize nonlinear dynamical systems, making their spectral information of crucial interest. Numerous algorithms have been developed to approximate these spectral properties, and Dynamic Mode Decomposition (DMD) stands…

Dynamical Systems · Mathematics 2023-11-13 Matthew J. Colbrook , Qin Li , Ryan V. Raut , Alex Townsend

In this paper, an extension to rules-based fault detection is demonstrated utilizing properties of the Koopman operator. The Koopman operator is an infinite-dimensional, linear operator that captures nonlinear, finite dimensional dynamics.…

Systems and Control · Computer Science 2017-03-22 Michael Georgescu , Sophie Loire , Don Kasper , Igor Mezic

We develop a new generalization of Koopman operator theory that incorporates the effects of inputs and control. Koopman spectral analysis is a theoretical tool for the analysis of nonlinear dynamical systems. Moreover, Koopman is intimately…

Optimization and Control · Mathematics 2016-02-25 Joshua L. Proctor , Steven L. Brunton , J. Nathan Kutz

The geometry of dynamical systems estimated from trajectory data is a major challenge for machine learning applications. Koopman and transfer operators provide a linear representation of nonlinear dynamics through their spectral…

Machine Learning · Statistics 2025-09-30 Thibaut Germain , Rémi Flamary , Vladimir R. Kostic , Karim Lounici

Dynamical systems provide a comprehensive way to study complex and changing behaviors across various sciences. Many modern systems are too complicated to analyze directly or we do not have access to models, driving significant interest in…

Dynamical Systems · Mathematics 2024-07-10 Matthew J. Colbrook , Igor Mezić , Alexei Stepanenko

The Koopman operator provides a powerful framework for representing the dynamics of general nonlinear dynamical systems. Data-driven techniques to learn the Koopman operator typically assume that the chosen function space is closed under…

Machine Learning · Statistics 2025-02-06 Boya Hou , Sina Sanjari , Nathan Dahlin , Alec Koppel , Subhonmesh Bose

Koopman operators and transfer operators represent dynamical systems through their induced linear action on vector spaces of observables, enabling the use of operator-theoretic techniques to analyze nonlinear dynamics in state space. The…

Dynamical Systems · Mathematics 2024-06-10 Claire Valva , Dimitrios Giannakis

The Koopman operator is a mathematical tool that allows for a linear description of non-linear systems, but working in infinite dimensional spaces. Dynamic Mode Decomposition and Extended Dynamic Mode Decomposition are amongst the most…

Machine Learning · Computer Science 2021-03-26 Francesco Zanini , Alessandro Chiuso

Koopman and Perron-Frobenius operators for dynamical systems have been getting popular in a number of fields in science these days. Properties of the Koopman operator essentially depend on the choice of function spaces where it acts.…

Dynamical Systems · Mathematics 2024-01-29 Masahiro Ikeda , Isao Ishikawa , Corbinian Schlosser

We provide an overview of the Koopman operator analysis for a class of partial differential equations describing relaxation of the field variable to a stable stationary state. We introduce Koopman eigenfunctionals of the system and use the…

Pattern Formation and Solitons · Physics 2021-06-04 Hiroya Nakao , Igor Mezić

The Koopman operator allows for handling nonlinear systems through a (globally) linear representation. In general, the operator is infinite-dimensional - necessitating finite approximations - for which there is no overarching framework.…

Systems and Control · Electrical Eng. & Systems 2021-12-23 Petar Bevanda , Stefan Sosnowski , Sandra Hirche

We develop a Koopman operator framework for studying the {computational properties} of dynamical systems. Specifically, we show that the resolvent of the Koopman operator provides a natural abstraction of halting, yielding a ``Koopman…

Mathematical Physics · Physics 2025-10-08 Francesco Caravelli , Jean-Charles Delvenne

Koopman operator describes evolution of observables in the phase space, which could be used to extract characteristic dynamical features of a nonlinear system. Here, we show that it is possible to carry out interesting symbolic partitions…

Chaotic Dynamics · Physics 2020-07-23 Cong Zhang , Yueheng Lan

The Koopman operator provides a linear perspective on non-linear dynamics by focusing on the evolution of observables in an invariant subspace. Observables of interest are typically linearly reconstructed from the Koopman eigenfunctions.…

Dynamical Systems · Mathematics 2024-03-06 Shaowu Pan , Karthik Duraisamy

We study the spectrum of one dimensional integral operators in bounded real intervals of length $2L$, for value of $L$ large. The integral operators are obtained by linearizing a non local evolution equation for a non conserved order…

Mathematical Physics · Physics 2017-01-16 Enza Orlandi , Carlangelo Liverani

The Koopman operator approach provides a powerful linear description of nonlinear dynamical systems in terms of the evolution of observables. While the operator is typically infinite-dimensional, it is crucial to develop finite-dimensional…

Dynamical Systems · Mathematics 2025-03-03 Rishikesh Yadav , Alexandre Mauroy

This paper proposes a unified family of learnable Koopman operator parameterizations that integrate linear dynamical systems theory with modern deep learning forecasting architectures. We introduce four learnable Koopman…

Machine Learning · Computer Science 2026-03-16 Ali Forootani , Raffaele Iervolino

We develop a framework for dimension reduction, mode decomposition, and nonparametric forecasting of data generated by ergodic dynamical systems. This framework is based on a representation of the Koopman and Perron-Frobenius groups of…

Dynamical Systems · Mathematics 2017-09-04 Dimitrios Giannakis

We provide a framework for learning of dynamical systems rooted in the concept of representations and Koopman operators. The interplay between the two leads to the full description of systems that can be represented linearly in a finite…

Dynamical Systems · Mathematics 2020-10-13 Igor Mezic