We study when interventions can robustly increase market surplus despite imprecise information about economic primitives, in a setting with many strategic firms possessing market power. The key sufficient condition, recoverable structure, requires large-scale product complementarities. The analysis works by decomposing the incidence of interventions in terms of principal components of a Slutsky matrix. Under recoverable structure, a noisy signal of this matrix reveals enough about these principal components to design robust interventions. Our results demonstrate the utility of spectral methods for analyzing imperfectly observed strategic interactions with many agents.

Players are endowed with resources. A player can engage in conflict with others to enlarge his resources. The set of potential conflicts is defined by a contiguity network. Players are farsighted and aim to maximize their resources. They decide on whether to wage war or remain peaceful. The winner of a war takes control of the loser's node and resources; he then decides on whether to wage war against other neighbours, or to stay peaceful. The game ends when either all players choose to be peaceful or when only one player is left.

No abstract available.

We develop a game-theoretic framework for the study of competition between firms who have budgets to "seed" the initial adoption of their products by consumers located in a social network. The payoffs to the firms are the eventual number of adoptions of their product through a competitive stochastic diffusion process in the network. This framework yields a rich class of competitive strategies, which depend in subtle ways on the stochastic dynamics of adoption, the relative budgets of the players, and the underlying structure of the social network.