On the geometry of singular Lagrangians (Q1580289)

This paper is devoted to study the natural geometry of singular Lagrangian systems, which suggests the transition principle, a prescription for what a phase trajectory must do when reaching a singular hypersurfaces \(S\). The authors observe the following fact: any Lagrangian, however degenerate it is, admits the corresponding Hamiltonian field, which is a relative one along the Legendre map.