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Georgia Southern University

Electronic Theses and Dissertations

Theses/Dissertations

Coadjoint orbit

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Explicit Pseudo-Kähler Metrics On Flag Manifolds, Thomas A. Mason Iii Jan 2020

Explicit Pseudo-Kähler Metrics On Flag Manifolds, Thomas A. Mason Iii

Electronic Theses and Dissertations

The coadjoint orbits of compact Lie groups each carry a canonical (positive definite) Kähler structure, famously used to realize the group's irreducible representations in holomorphic sections of certain line bundles (Borel-Weil theorem). Less well-known are the (indefinite) invariant pseudo-Kähler structures they also admit, which can be used to realize the same representations in higher cohomology of the sections (Bott), and whose analogues in a non-compact setting lead to new representations (Kostant-Langlands). The purpose of this thesis is to give an explicit description of these metrics in the case of the unitary group G=Un.


A Constructive Proof Of The Borel-Weil Theorem For Classical Groups, Kostiantyn Timchenko Jan 2014

A Constructive Proof Of The Borel-Weil Theorem For Classical Groups, Kostiantyn Timchenko

Electronic Theses and Dissertations

The Borel-Weil theorem is usually understood as a realization theorem for representations that have already been shown to exist by other means (``Theorem of the Highest Weight''). In this thesis we turn the tables and show that, at least in the case of the classical groups $G = U(n)$, $SO(n)$ and $Sp(2n)$, the Borel-Weil construction can be used to quite explicitly prove existence of an irreducible representation having highest weight $\lambda$, for each dominant integral form $\lambda$ on the Lie algebra of a maximal torus of $G$.


Homogeneous Symplectic Manifolds Of The Galilei Group, Michael S. Davis Jan 2012

Homogeneous Symplectic Manifolds Of The Galilei Group, Michael S. Davis

Electronic Theses and Dissertations

In this thesis we classify all symplectic manifolds admitting a transitive, 2-form preserving action of the Galilei group G. Using the moment map and a theorem of Kirillov-Kostant-Souriau, we reduce the problem to that of classifying the coadjoint orbits of a central extension of G discovered by Bargmann. We then develop a systematic inductive technique to construct a cross section of the coadjoint action. The resulting symplectic orbits are interpreted as the manifolds of classical motions of elementary particles with or without spin, mass, and color.