2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/127777In this note, we consider generalizations of the asymptotic Hopf invariant, or helicity, for Hamiltonian systems with one-and-a-half degrees of freedom and symplectic diffeomorphisms of a two-disk to itself.7 pagesDifferential GeometryDynamical Systems37J05, 55Q25text