2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187559We construct a Hamiltonian formulation for the class of plane-fronted gravitational waves with parallel rays (pp-waves). Because of the existence of a light-like Killing vector, the dynamics is effectively reduced to a 2+1 evolution with "time" chosen to be light-like. In spite of the vanishing action this allows us to geometrically identify a symplectic form as well as dynamical Hamiltonian, thus casting the system into canonical form.To appear in the "Obregon Festschrift"General Relativity and Quantum Cosmologytext