Relative Critical Points

Relative equilibria of Lagrangian and Hamiltonian systems with symmetry are critical points of appropriate scalar functions parametrized by the Lie algebra (or its dual) of the symmetry group. Setting aside the structures – symplectic, Poisson, or variational – generating dynamical systems from such...

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Published in:Symmetry, Integrability and Geometry: Methods and Applications
Date:2013
Main Author: Lewis, D.
Format: Article
Language:English
Published: Інститут математики НАН України 2013
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/149195
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Relative Critical Points / Lewis D. // Symmetry, Integrability and Geometry: Methods and Applications. — 2013. — Т. 9. — Бібліогр.: 53 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-149195
record_format dspace
spelling Lewis, D.
2019-02-19T18:29:11Z
2019-02-19T18:29:11Z
2013
Relative Critical Points / Lewis D. // Symmetry, Integrability and Geometry: Methods and Applications. — 2013. — Т. 9. — Бібліогр.: 53 назв. — англ.
1815-0659
2010 Mathematics Subject Classification: 37J15; 53D20; 58E09; 70H33
DOI: http://dx.doi.org/10.3842/SIGMA.2013.038
https://nasplib.isofts.kiev.ua/handle/123456789/149195
Relative equilibria of Lagrangian and Hamiltonian systems with symmetry are critical points of appropriate scalar functions parametrized by the Lie algebra (or its dual) of the symmetry group. Setting aside the structures – symplectic, Poisson, or variational – generating dynamical systems from such functions highlights the common features of their construction and analysis, and supports the construction of analogous functions in non-Hamiltonian settings. If the symmetry group is nonabelian, the functions are invariant only with respect to the isotropy subgroup of the given parameter value. Replacing the parametrized family of functions with a single function on the product manifold and extending the action using the (co)adjoint action on the algebra or its dual yields a fully invariant function. An invariant map can be used to reverse the usual perspective: rather than selecting a parametrized family of functions and finding their critical points, conditions under which functions will be critical on specific orbits, typically distinguished by isotropy class, can be derived. This strategy is illustrated using several well-known mechanical systems – the Lagrange top, the double spherical pendulum, the free rigid body, and the Riemann ellipsoids – and generalizations of these systems.
This paper is a contribution to the Special Issue “Symmetries of Dif ferential Equations: Frames, Invariants and Applications”. The full collection is available at http://www.emis.de/journals/SIGMA/SDE2012.html. The author is indebted to the referees for their many valuable suggestions and corrections. Their insightful contributions greatly improved this work.
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
Relative Critical Points
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Relative Critical Points
spellingShingle Relative Critical Points
Lewis, D.
title_short Relative Critical Points
title_full Relative Critical Points
title_fullStr Relative Critical Points
title_full_unstemmed Relative Critical Points
title_sort relative critical points
author Lewis, D.
author_facet Lewis, D.
publishDate 2013
language English
container_title Symmetry, Integrability and Geometry: Methods and Applications
publisher Інститут математики НАН України
format Article
description Relative equilibria of Lagrangian and Hamiltonian systems with symmetry are critical points of appropriate scalar functions parametrized by the Lie algebra (or its dual) of the symmetry group. Setting aside the structures – symplectic, Poisson, or variational – generating dynamical systems from such functions highlights the common features of their construction and analysis, and supports the construction of analogous functions in non-Hamiltonian settings. If the symmetry group is nonabelian, the functions are invariant only with respect to the isotropy subgroup of the given parameter value. Replacing the parametrized family of functions with a single function on the product manifold and extending the action using the (co)adjoint action on the algebra or its dual yields a fully invariant function. An invariant map can be used to reverse the usual perspective: rather than selecting a parametrized family of functions and finding their critical points, conditions under which functions will be critical on specific orbits, typically distinguished by isotropy class, can be derived. This strategy is illustrated using several well-known mechanical systems – the Lagrange top, the double spherical pendulum, the free rigid body, and the Riemann ellipsoids – and generalizations of these systems.
issn 1815-0659
url https://nasplib.isofts.kiev.ua/handle/123456789/149195
citation_txt Relative Critical Points / Lewis D. // Symmetry, Integrability and Geometry: Methods and Applications. — 2013. — Т. 9. — Бібліогр.: 53 назв. — англ.
work_keys_str_mv AT lewisd relativecriticalpoints
first_indexed 2025-12-07T15:52:47Z
last_indexed 2025-12-07T15:52:47Z
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