The number of edges <i>e</i>(<i>t</i>) versus the number of nodes <i>n</i>(<i>t</i>) in accumulated transaction networks in log coordinate.

The red lines show fitted power-law distribution for the networks. In the figure’s equation, x represents the number of nodes and represents the fitting number of edges, and the exponents are 1.15, 1.00, 1.05, respectively.