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Main Authors: Meng, Yiming, Zhou, Ruikun, Ornik, Melkior, Liu, Jun
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2403.15688
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author Meng, Yiming
Zhou, Ruikun
Ornik, Melkior
Liu, Jun
author_facet Meng, Yiming
Zhou, Ruikun
Ornik, Melkior
Liu, Jun
contents The Koopman operator has gained significant attention in recent years for its ability to verify evolutionary properties of continuous-time nonlinear systems by lifting state variables into an infinite-dimensional linear vector space. The challenge remains in providing estimations for transitional properties pertaining to the system's vector fields based on discrete-time observations. To retrieve such infinitesimal system transition information, leveraging the structure of Koopman operator learning, current literature focuses on developing techniques free of time derivatives through the use of the Koopman operator logarithm. However, the soundness of these methods has so far been demonstrated only for maintaining effectiveness within a restrictive function space, together with knowledge of the operator spectrum properties. To better adapt to the practical applications in learning and control of unknown systems, we propose a logarithm-free technique for learning the infinitesimal generator without disrupting the Koopman operator learning framework. This approach claims compatibility with other system verification tools using the same set of training data. We provide numerical examples to demonstrate its effectiveness in applications of system identification and stability prediction.
format Preprint
id arxiv_https___arxiv_org_abs_2403_15688
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Koopman-Based Learning of Infinitesimal Generators without Operator Logarithm
Meng, Yiming
Zhou, Ruikun
Ornik, Melkior
Liu, Jun
Dynamical Systems
The Koopman operator has gained significant attention in recent years for its ability to verify evolutionary properties of continuous-time nonlinear systems by lifting state variables into an infinite-dimensional linear vector space. The challenge remains in providing estimations for transitional properties pertaining to the system's vector fields based on discrete-time observations. To retrieve such infinitesimal system transition information, leveraging the structure of Koopman operator learning, current literature focuses on developing techniques free of time derivatives through the use of the Koopman operator logarithm. However, the soundness of these methods has so far been demonstrated only for maintaining effectiveness within a restrictive function space, together with knowledge of the operator spectrum properties. To better adapt to the practical applications in learning and control of unknown systems, we propose a logarithm-free technique for learning the infinitesimal generator without disrupting the Koopman operator learning framework. This approach claims compatibility with other system verification tools using the same set of training data. We provide numerical examples to demonstrate its effectiveness in applications of system identification and stability prediction.
title Koopman-Based Learning of Infinitesimal Generators without Operator Logarithm
topic Dynamical Systems
url https://arxiv.org/abs/2403.15688