Poisson quasi-Nijenhuis manifolds, closed Toda lattices, and generalized recursion relations

Abstract

We present two involutivity theorems in the context of Poisson quasi-Nijenhuis manifolds. The second one stems from recursion relations that generalize the so-called Lenard–Magri relations on a bi-Hamiltonian manifold. We apply these results to the closed (or periodic) Toda lattices of type \(A_n^{(1)}\), \(C_n^{(1)}\), \(A_{2n}^{(2)}\), and, for the ones of type \(A^{(1)}_n\), we show how this geometrical setting relates to their bi-Hamiltonian representation and to their recursion relations.