find the maximum flow f and a minimum cut. (b) draw the residual graph gf (along with its edge capacities). in this residual network, mark the vertices reachable from s and the vertices from which t is reachable. (c) an edge of a network is called a bottleneck edge if increasing its capacity results in an increase in the maximum flow. list all bottleneck edges in the above network. (d) give a very simple example (containing at most four nodes) of a network which has no bottleneck edges. (e) give an efficient algorithm to identify all bottleneck edges in a network. (hint: start by running the usual network flow algorithm, and then examine the residual graph.)