2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73849Write f(n) for the minimum number of 4-cliques in graphs of order n with triangle-free complement. Finding f(n) is a particular case of a problem raised by Erdos in 1962. We give an upper bound of f(n) and a matching lower bound when the graph is close to regular.8 pagesCombinatorics05C35text