2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49804Using the commutativity of a general variation with the time differentiation we discuss both global and local (gauge) symmetries of a lagrangian from a unified point of view. The Noether considerations are thereby applicable for both cases. A complete equivalence between the hamiltonian and lagrangian formulations is established.Revtex, 4 pages, no figuresHigh Energy Physics - Theorytext