Figure 1

Simple illustration of betweenness. Link e₁ = (i₁,j₁) (shown red) features in any path between a node on the 'left’ of the network (there are 6) and a node on the 'right’ (of which there are 5) and therefore has a relatively high betweenness value of 60. Link e₂ = (i₂,j₂) (blue), on the other hand, is only traversed by paths starting or ending at j₂; there are 20 such paths and it therefore has a relatively low betweenness value of 20.