Before revision:  Both T and G have the same node set, and for every node pair s,t, the minimum st-cut in T is also an exact minimum st-cut in G. We give the first subcubic-time algorithm that constructs such a tree for an unweighted graph G . Its time complexity is O(n^{ 2.75 }), for n=|V(G)|;
After revision:  Both T and G have the same node set, and for every node pair s,t, the minimum st-cut in T is also an exact minimum st-cut in G. We give the first subcubic-time algorithm that constructs such a tree for an unweighted graph G . Its time complexity is O(n^{ 2.5 }), for n=|V(G)|;