Coherence of dynamic choices and strategic interactions.

Summary The purpose of this thesis is to study the coherence of dynamic choices in various contexts of strategic interaction. Three themes are more particularly addressed: the coordination of decisions, the irreversibility of choices and the value of information. The first part of the thesis is devoted to the coordination of agents' strategies in continuous games with almost perfect information. Our goal is to show how the introduction of public signals is necessary to guarantee the existence of perfect equilibria in this class of games. To do so, we develop an original analysis method, based on the notion of continuation correspondence. The second part of the thesis deals with information acquisition in the context of dynamically inconsistent preferences. We show that, in the absence of commitment on future decisions, an agent with such preferences can be led to voluntarily restrict the information at his disposal, in order to optimally constrain his present and future choices. This strategic ignorance behavior is more efficient than exhaustive information acquisition. The last part of the thesis is devoted to the option value of information in the presence of irreversible choices. Two models are studied for this purpose. In the first one, we analyze the dynamics of investment in a market where demand fluctuates stochastically. We show that in a monopoly, investments are systematically postponed with respect to the social optimum. In duopoly, we determine the impact of the threat of preemption on the option value of waiting. In a second model, we examine how opportunistic political parties choose their candidates based on the information available about them. We characterize the type of inefficiencies to which the parties' strategic behavior gives rise. Finally, we show that a dynamic perspective modifies the candidate selection strategy within a party by increasing the incentives to replace a candidate if he or she fails to perform.