2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33661This paper reviews the construction of quantum field theory on a 4-dimensional spacetime by combinatorial methods, and discusses the recent developments in the direction of a combinatorial construction of quantum gravity.amslatex, 7 pages, ICMP conference talkGeneral Relativity and Quantum Cosmologytext