Let G=(U,V,E) be an undirected bipartite graph. The paper specifies some procedures that allows the following 3-partition of the set E to be made efficiently: E1 is the set of edges belonging to all the maximum matchings (1-persistent edges); EÅ0 is the set of edges belonging to no maximum matching (0-persistent edges); EÅw is the set of edges belonging to at least one maximum matching but not to all of them (weakly persistent edges).
