Simulation and analytic results of the distribution of the number of cooperators.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049663#s2" target="_blank">Results</a> are obtained in a simulation of time steps (violet open circles). Considering time steps with , the value of are found as the fraction of steps with exactly cooperators. The parameters are the same as those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049663#pone-0049663-g011" target="_blank">Figure 11</a>. The red solid line represents the the analytic results as given by <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049663#pone.0049663.e022" target="_blank">Eq.(2)</a>.