2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/35348In this talk the description of gauge theories associated with internal symmetries is extended to the case in which the symmetry group is the space-time translation group (recovering Einstein's theory) using the standard jet-bundle formalism. We also reformulate these theories introducing the idea of jet-gauge and jet-diffeomorphism groups. Finally, we attempt to a simple, yet non-trivial, mixing of gravity and electromagnetism (or more general internal interaction) by turning to gauge symmetry a central extension of the Poincare group.Plenary talk presented at Workshop on High Energy Physics&Field Theory (Protvino, Russia, 2004)General Relativity and Quantum Cosmologytext