Equation (13.74) tells us on average how many vertices are a distance d away from a given vertex.
a) Assuming that this expression works for all values of d (which is only a rough approximation to the truth), at what value of d is this average number of vertices equal to the number n in the whole network?
b) Hence derive a rough expression for the diameter of the network in terms of C1 and C2, and so argue that configuration model networks display the small-world effect in the sense that typical geodesic distances between vertices are O(log n).
