once at the start of the game, before the first round of attack; thereafter the game proceeds attack – replenish – adapt.

An attack strategy is more efficient, for a given defense strategy, if an attacker using it requires a smaller budget to disrupt the network. Similarly, a defense strategy is more efficient if, for a given attack strategy, it compels the attacker to expend a higher budget to achieve network disruption. (We will clarify this later once we have presented and discussed a few simulations.)

We assume initially that the attacker has perfect information about the network topology, and that her goal is simply to partition the network – that is, divide it into two or more nontrivial disjoint components. We assume that the defender has only local information, that it, each node shares the information available to those nodes with which it is connected. Thus, for example, if the attacker manages to split the network into two components, there is no way for them to reconnect. We also start off by assuming that the defence strategy affects only the adaptation phase, as only once nodes have connected to a network can they be programmed to follow it; so 