Lie algebra pairing and the Lagrangian and Hamiltonian equations in gauge-invariant problems

Abstract

Let P → M be a principal G-bundle over a pseudo-Riemannian manifold (M, g). If G is semisimple, the Euler-Lagrange and the Hamilton-Cartan equations of the Yang-Mills Lagrangian defined by g are proved to remain unchanged if the Cartan-Killing metric is replaced by any other non-degenerate, adjoint-invariant bilinear form on the Lie algebra