FIG. 4.

Logarithmic plot of the order parameter, $r$, for (a) the RGs and (b) the SFNs with $N={10}^4$ (red circles), ${10}^5$ (green triangles), and ${10}^6$ (blue squares). The open symbols and solid symbols represent the results of $f=0.01$ and 0.2, respectively. Two vertical lines represent the epidemic threshold $T_c$ of $f=0.01$ (left) and $f=0.2$ (right) as given by Eq. (5).