Degree distribution of several similar fractal scale-free networks. The degree distribution of the tree-like skeleton satisfies . The sizes of these networks are N = 600, 800, and 1200 respectively, and the local link probabilities of these networks are respectively p = 0.0951, 0.0821, and 0.0660. The network degree distribution satisfies the power-law form . From the slope of the line in the figure, we get γ = 0.90. The numerical results are the average over network realizations.