Before revision: A feasible network is a subset S of E, such that there is a path between every two nodes u and v, and the sum of w(u,v) for all (u,v) in S is at most B .
After revision: A feasible network is a subset S of E, such that , and there is a path between every two nodes u and v (that is, S contains a spanning tree of G) the sum of w(u,v) for all (u,v) in S is at most B .