As we know, now there is efficient algorithms to find the overall min-cut in a directed graph, e.g. Hao and Orlin (1994). % z. X* L& N! v! h 5 i( L- a9 Y6 jNow my problem is to find an overall min-cut just separating some given node pairs, not all the node pairs. For example, I have an 8-node digraph with capacities on each arc and want to find the overall min-cut separating some node pairs such as 8 and 1, 6 and 3, 7 and 1. The algorithm of Hao and Orlin (1994) cannot solve my problem. % k& T$ v" U- r7 o4 ~& P- K; k