2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/106015In this review we report on how the problem of general covariance is treated within the algebraic approach to quantum field theory by use of concepts from category theory. Some new results on net cohomology and superselection structure attained in this framework are included.61 pages, 3 figures, LaTeXMathematical Physicstext