Convexity properties of Hamiltonian group actions
Author(s)
Bibliographic Information
Convexity properties of Hamiltonian group actions
（CRM monograph series, v. 26）
Americam Mathematical Society, c2005
Available at 16 libraries
Note
Includes bibliographical references
Description and Table of Contents
Description
This is a monograph on convexity properties of moment mappings in symplectic geometry. The fundamental result in this subject is the Kirwan convexity theorem, which describes the image of a moment map in terms of linear inequalities. This theorem bears a close relationship to perplexing old puzzles from linear algebra, such as the Horn problem on sums of Hermitian matrices, on which considerable progress has been made in recent years following a breakthrough by Klyachko. The book presents a simple local model for the moment polytope, valid in the ""generic"" case, and an elementary Morse-theoretic argument deriving the Klyachko inequalities and some of their generalizations. It reviews various infinite-dimensional manifestations of moment convexity, such as the Kostant type theorems for orbits of a loop group (due to Atiyah and Pressley) or a symplectomorphism group (due to Bloch, Flaschka and Ratiu).Finally, it gives an account of a new convexity theorem for moment map images of orbits of a Borel su This volume is recommended for independent study and is suitable for graduate students and researchers interested in symplectic geometry, algebraic geometry, and geometric combinatorics. Information for our distributors: Titles in this series are co-published with the Centre de Recherches Mathematiques.
Table of Contents
Introduction The convexity theorem for Hamiltonian $G$-spaces A constructive proof of the non-abelian convexity theorem Some elementary examples of the convexity theorem Kahler potentials and convexity Applications of the convexity theorem Bibliography.
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