Co-Evolution in the PD for Different Time Scales

<div><p>PD with <i>b/c =</i> 2 (<i>T =</i> 2,<i>S = −</i>1 and <i>β =</i> 0.005).</p><p>(Upper panel) Fraction of cooperators at end as a function of <i>W</i> for different values of <i>z,</i> each drawn with a different color. For each value of <i>z,</i> there is a critical value of <i>W</i> − <i>W_critical</i>— above which cooperators wipe out defectors.</p><p>(Lower panel) Maximum value of the connectivity in population as a function of <i>W.</i> With increasing <i>z, W_critical</i> increases. In all cases, the heterogeneity of the associated network becomes maximal at <i>W_critical,</i> stagnating for higher values.</p>