2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/119613Through the discussion of the fundamental properties of Lagrangian density for a gravitational system, the theoretical foundations of the modified Einstein field equations and the Lorentz and Levi-Civita conservation laws are systematically studied. Our study confirms the view that they could be used as the premises to establish a new cosmology.17 pages, no figureGeneral Physicstext