Linear Poisson Structures and Lie Algebras

Abstract

AbstractTogether with symplectic manifolds, considered in the previous chapter, Lie algebras provide the first examples of Poisson manifolds. The dual \(\mathfrak{g}^{*}\) of a finite-dimensional Lie algebra \(\mathfrak{g}\) admits a natural Poisson structure, called its Lie–Poisson structure. It is a linear Poisson structure and every linear Poisson structure (on a finite-dimensional vector space) is a Lie–Poisson structure. We show that the leaves of the symplectic foliation are the coadjoint orbits of the adjoint group of \(\mathfrak{g}\) and we shortly discuss the linearization of Poisson structures (in the neighborhood of a point where the rank is zero). Using a non-degenerate Ad-invariant symmetric bilinear form, we get the Lie-Poisson structure on \(\mathfrak{g}\), which has several virtues, amongst which the fact that the Hamiltonian vector fields on \(\mathfrak{g}\) take a natural form, a so-called Lax form. Affine Poisson structures and their Lie theoretical interpretation are discussed at the end of the chapter.KeywordsModular FormPoisson BracketPoisson StructureCoadjoint OrbitPoisson ManifoldThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.