Figure 4. The fundamental differences between a random network (for example an Erdős-Rényi network) and a scale free network. a) shows a random network of N = 10 and P = 0.2. This type of network grows with a homogeneous degree distribution, i.e., K ≈ < K > and the degree function grows in the same way as for a Poisson distribution (c); where most of the nodes (e) have more or less the same number of links (red dots) as their neighboring nodes (green dots). (b) In contrast, scale free networks are non-homogeneous, the characteristic degree distribution is not peaked and instead approximates a power law (d); these types of network grow preferentially around a few nodes “Hubs” -the red dots- where most of the links are concentrated: green dots (f) (Barabási, 2003).