A polynomial cycle canceling algorithm for submodular flows

Submodular ow problems, introduced by Edmonds and Giles 2], generalize network ow problems. Many algorithms for solving network ow problems have been generalized to submodular ow problems (cf. references in Fujishige 4]), e.g. the cycle canceling method of Klein 9]. For network ow problems, the choice of minimum-mean cycles in Goldberg and Tarjan 6], and the choice of minimum-ratio cycles in Wallacher 12] lead to polynomial cycle canceling methods. For submodular ow problems, Cui and Fujishige 1] show niteness for the minimum-mean cycle method while Zimmermann 16] develops a pseudo-polynomial minimum ratio cycle method. Here, we prove pseudo-polynomiality of a larger class of the minimum-ratio variants and, by combining both methods, we develop a polynomial cycle canceling algorithm for submodular ow problems.