Pursuit-Evasion in Models of Complex Networks

Vertex pursuit games, such as the game of Cops and Robbers, are a simplified model for network security. In these games, cops try to capture a robber loose on the vertices of the network. The minimum number of cops required to win on a graph G is the cop number of G. We present asymptotic results for the game of Cops and Robbers played in various stochastic network models, such as in G(n, p) with non-constant p, and in random power law graphs. We find bounds for the cop number of G(n, p) for a large range of p as a function of n. We prove that the cop number of random power law graphs with n vertices is asymptotically almost surely Θ(n). The cop number of the core of random power law graphs is investigated, and is proved to be of smaller order than the order of the core.