文摘
Given a connected graph and three even-sized subsets , , of V, when does V have a partition such that is connected and is odd for all and ? This problem arises in the area of integer flow theory and has theoretical interest in its own right. The special case when has been resolved by Chakravarti and Robertson, and the general problem can be rephrased as a problem on binary matroids that asks if a given triple of elements is contained in a circuit. The purpose of this paper is to present a complete solution to this problem based on a strengthening of Seymour?s theorem on triples in matroid circuits.