On minimizing symmetric set functions

Mader proved that every loopless undirected graph contains a pair (u,v) of nodes such that the star of u is a minimum cut separating u and v. Nagamoch i and Ibaraki showed that the last two nodes of a "max-back order" form suc h a pair and used this fact to develop an elegant min-cut algorithm. M. Que yranne extended this approach to minimize symmetric submodular functions. W ith the help of a short and simple proof, here we show that the same algori thm works for an even more general class of set functions.