2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/36615The representation theory of non-centrally extended Lie algebras of Noether symmetries, including spacetime diffeomorphisms and reparametrizations of the observer's trajectory, has recently been developped. It naturally solves some long-standing problems in quantum gravity, e.g. the role of diffeomorphisms and the causal structure, but some new questions also arise.14 pages, LaTexGeneral Relativity and Quantum Cosmologytext