of cooperators in the steady state, as a function of the clustering of the networks. The highest clustering value corresponds to the ordered network (lattice or ring), and networks get increasingly disordered as $C$ is decreased.

![ Steady cooperator density $\rho_c$ as a function of the clustering coefficient $C$, for $k=4$ and $\rho_c(0)=0.5$. (l) and (r) in the caption refer to lattice and ring networks respectively.[]{data-label="k4"}](imik4.eps)

![ Steady cooperator density $\rho_c$ as a function of the clustering coefficient $C$, for $K=6$ and $\rho_c(0)=0.5$. (l) and (r) in the caption refer to lattice and ring networks respectively.[]{data-label="k6"}](imik6.eps)

We begin by analyzing what happens for evolutions whose initial state consists of the same number of cooperators and defectors. In other words, the initial probability that a given agent is a cooperator is $0.5$. In this case, the steady state is always composed by a finite fraction of cooperators. As can be seen in the figures, there are some features that are common to all the families of networks analyzed. The first is that, for each class of network, the behaviors of the curves is qualitatively the same for the two values of $t$ used. The only difference is that, as is to 