“…For example, let us start from the network in the left hand side of Figure 1. 5 , x 6 } and θ 3 = {x 6 , x 3 , x 2 , x 4 , x 1 , x 5 } be three different orderings. If we apply the previous process, for θ 1 we recover the original graph, for θ 2 we obtain the second graph, and for the ordering θ 3 we get the much more dense graph on the right hand side of the same figure.…”