Sensitivity of equilibrium behavior to higher-order beliefs in nice games

We analyze “nice” games (where action spaces are compact intervals, utilities continuous and strictly concave in own action), which are used frequently in classical economic models. Without making any “richness” assumption, we characterize the sensitivity of any given Bayesian Nash equilibrium to hi...

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Bibliographic Details
Main Authors: Weinstein, Jonathan, Yildiz, Muhamet
Other Authors: Massachusetts Institute of Technology. Department of Economics
Format: Article
Language:en_US
Published: Elsevier 2015
Online Access:http://hdl.handle.net/1721.1/98466
https://orcid.org/0000-0002-7637-7117
Description
Summary:We analyze “nice” games (where action spaces are compact intervals, utilities continuous and strictly concave in own action), which are used frequently in classical economic models. Without making any “richness” assumption, we characterize the sensitivity of any given Bayesian Nash equilibrium to higher-order beliefs. That is, for each type, we characterize the set of actions that can be played in equilibrium by some type whose lower-order beliefs are all as in the original type. We show that this set is given by a local version of interim correlated rationalizability. This allows us to characterize the robust predictions of a given model under arbitrary common knowledge restrictions. We apply our framework to a Cournot game with many players. There we show that we can never robustly rule out any production level below the monopoly production of each firm.