2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/109099We give a very short self-contained combinatorial proof of the Babson-Kozlov conjecture, by presenting a cochain whose coboundary is the desired power of the characteristic class.2 pagesAlgebraic TopologyCombinatorics55M35; 05C15, 57S17Cobounding odd cycle coloringstext