FINDING CLIQUES IN SOCIAL NETWORKS: A NEW DISTRIBUTION-FREE MODEL

摘要

We propose a new distribution-free model of social networks. Our definitions are motivated by one of the most universal signatures of social networks, triadic closure the property that pairs of vertices with common neighbors tend to be adjacent. Our most basic definition is that of a c-closed graph, where for every pair of vertices u, v with at least c common neighbors, u and v are adjacent. We study the classic problem of enumerating all maximal cliques, an important task in social network analysis. We prove that this problem is fixed-parameter tractable with respect to c on c-closed graphs. Our results carry over to weakly c-closed graphs, which only require a vertex deletion ordering that avoids pairs of nonadjacent vertices with c common neighbors. Numerical experiments show that well-studied social networks with thousands of vertices tend to be weakly c-closed for modest values of c.