Abstracts Economics

Information-revelation in incomplete-information games

by Kjell Åke Nygren

Our thesis concentrates on information-revelation in games with incomplete infor-mation. In chapter 2, we examine a one-shot version of a particular formulation of games with incomplete information due to Harsanyi [10]. The chaper examines the extent to which all interior Bayesian equilibria of such games are fully information-revealing as well as the extent to which the number of interior Bayesian equilibria is finite. One of our theorems states that, given a fixed common prior, the two proper¬ties hold generically in the space of twice continuously differentiable utility function bundles. Another theorem states that for a generic choice of a sufficiently smooth utility function bundle, the two properties hold generically in the space of common priors. In chapter 3, we model information in a one period setting using information partitions for the players. Our main result in this chapter states that in the space of twice continuously differentiable utility function bundles, it is a generic property of interior equilibria to yield full information-revelation. In chapter 4, we consider a two period model with incomplete information. Again, the information of the players is modeled using information partitions. One of the results in this chapter demonstrates that second period beliefs satisfying certain sym¬metry assumptions are uniquely determined even for information sets that are un¬reached in equilibrium. Using these beliefs, we formulate a two-period equilibrium concept. Another result demonstrates that if the information structure satisfies an informational dispersion assumption, generic existence of two-period equilibria can be demonstrated in the space of twice continuously differentiable first period utility function bundles.