2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/35833The concept of time is discussed in the context of the canonical formulation of the gravitational field. Using a hypersurface orthogonal foliation, the arbitrariness of the lapse function is eliminated and the shift vector vanishes, allowing a consistent definition of time.10 pages, Revtex, no figures, email maia@mat.unb.brGeneral Relativity and Quantum Cosmologytext