2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/59723We discuss symplectic manifolds where, locally, the structure is that encountered in Lagrangian dynamics. Exemples and characteristic properties are given. Then, we refer to the computation of the Maslov classes of a Lagrangian submanifold. Finally, we indicate the generalization of this type of structures to Poisson manifolds.LaTex, 21 pages. Lecture at ``Poisson 2000'', CIRM, Luminy, France, June 26-30, 2000Symplectic Geometry53D05, 53D12, 53D17text