Epidemic threshold <i>λ</i>_<i>c</i> as a function of the rewiring probability for different spatial constraints <i>R</i> on the interconnection links.

<p>For a given rewiring probability <i>p</i> and a given spatial constraint <i>R</i>, we gradually increase the infection rate <i>λ</i> and find the corresponding infection density in the steady state for each infection rate. We consider <i>λ</i>_<i>c</i> as the first <i>λ</i> value corresponding to a non-zero infection density in the steady state. Each component network has a small-world topology with a rewiring probability <i>p</i>. The density of the interconnection links is <i>q</i> = 1. Initially, 10% of the nodes in network A are randomly chosen to be infected. The network size is <i>N</i> = 10000. The results have been averaged over 100 realizations.