Convexity and Commuting Hamiltonians

Authors: Michael Atiyah - Bulletin of the London Mathematical Society 1982 cited by 972

A well-known result of Schur [9] asserts that the diagonal elements (al,..., an) of annxn Hermitian matrix A satisfy a system of linear inequalities involving the eigenvalues (Xi,..., Xn). In geometric terms, regarding a and k as points in R " and allowing the symmetric group £ „ to act by permutation of coordinates, this result