2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77139In a directed graph, the imbalance of a vertex is its outdegree minus its indegree. We characterize the sequences that are realizable as the sequence of imbalances of a simple directed graph. Moreover, a realization of a realizable sequence can be produced by a greedy algorithm.5 pagesCombinatorics05C20text