Non-symplectic symmetries and bi-Hamiltonian structures of the rational harmonic oscillator

Hamiltonian and Symplectic Symmetries: an Introduction

Classical mechanical systems are modeled by a symplectic manifold (M,ω), and their symmetries are encoded in the action of a Lie group G on M by diffeomorphisms which preserve ω. These actions, which are called symplectic, have been studied in the past forty years, following the works of Atiyah, Delzant, Duistermaat, Guillemin, Heckman, Kostant, Souriau, and Sternberg in the 1970s and 1980s on ...

Bi–Hamiltonian Structures and Solitons

Methods in Riemann–Finsler geometry are applied to investigate bi–Hamiltonian structures and related mKdV hierarchies of soliton equations derived geometrically from regular Lagrangians and flows of non–stretching curves in tangent bundles. The total space geometry and nonholonomic flows of curves are defined by Lagrangian semisprays inducing canonical nonlinear connections (N–connections), Sas...

Symmetries of Hamiltonian systems on symplectic and Poisson manifolds

Non-Hamiltonian symplectic torus actions

An action of a torus T on a compact connected symplectic manifold M is Hamiltonian if it admits a momentum map, which is a map on M taking values in the dual of the Lie algebra of T. In 1982, Atiyah and GuilleminSternberg proved that the image of the momentum map is a convex polytope, now called the momentum polytope. In 1988, Delzant showed that if the dimension of T is half of the dimension o...

Flat Bi-Hamiltonian Structures and Invariant Densities

A bi-Hamiltonian structure is a pair of Poisson structures P , Q which are compatible, meaning that any linear combination αP+βQ is again a Poisson structure. A biHamiltonian structure (P,Q) is called flat if P and Q can be simultaneously brought to a constant form in a neighborhood of a generic point. We prove that a generic biHamiltonian structure (P,Q) on an odd-dimensional manifold is flat ...