Integrability of invariant metrics on the Virasoro group
Résumé
Each right-invariant metric on the Virasoro group induces a Hamiltonian vector field on the dual of the Lie algebra of the Virasoro algebra equipped with the canonical Lie-Poisson structure. We show that the Hamiltonian vector fields Xk induced by the metrics given at the identity by the Hk Sobolev inner products are bi-Hamiltonian relative to a modified Lie-Poisson structure only for k=0 and k=1.