Figure 3
From: Graph theoretical analysis of complex networks in the brain
Scale-free graphs are characterized by a scale-free degree distribution P(k). In scale-free graphs, different vertices have very different degrees, and typically a few vertices with extremely high degrees (so-called 'hubs') are present. In the schematic example shown here the white (k = 9) and the striped (k = 7) vertices are examples of hubs.