A simple existence criterion for (g < f)- factors

AbstractWe simplify the criterion of Lovász for the existence of a (g, ƒ)-factor when g < ƒ, or when the graph is bipartite. Moreover, we give a simple direct proof, implying an O((g(V)) · |E|) algorithm, for these cases. We then illustrate the convenience of the new criterion by deriving some old and some new facts about (g,ƒ)-factors and [a,b]-factors