2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/116431We give a simple proof of Tutte's theorem stating that the cycle space of a 3--connected graph is generated by the set of non-separating circuits of the graph. Keywords: graph, cycle, circuit, cycle space, non-separating circuit, strong isomorphism.Combinatorics05C10text