A New Model for a Scale-Free Hierarchical Structure of Isolated Cliques

摘要

Scale-free networks are usually defined as the ones that have power-law degree distributions. Since many of real world networks such as the World Wide Web, the Internet, citation networks, biological networks, and so on, have this property in common, scale-free networks have attracted interests of researchers so far. They also revealed that such networks have some typical properties such as high cluster coefficient and small diameter as well, and a lot of network models have been proposed to explain them. Recently, some new observations for a real world network are reported [12]. It tries to find a special kind of cliques from a network and introduces observations; 1. the size distributions of cliques show a power-law, 2. the degree distribution of the network after contracting those cliques show a power-law, and 3. by regarding the contracted network as the original, 1 and 2 are observed repeatedly. In this paper, we propose a new network model constructed by a 'clique expansion' procedure, to explain these new hierarchical structure of cliques.