On the relationship between robustness to incomplete information and noise-independent selection in global games

This note demonstrates that a symmetric 3×3 supermodular game may fail to have any equilibrium robust to incomplete information. Since the global game solution in symmetric 3×3 supermodular games is known to be independent of the noise structure, this result implies that a noise-independent selection in global games may not be a robust equilibrium. Our proof reveals that the assumption in global games that the noise errors are independent of the state imposes a non-trivial restriction on incomplete information perturbations.     

Coordinating under incomplete information

We show that, in a minimum effort game with incomplete information where player types are independently drawn, there is a largest and smallest Bayesian equilibrium, leading to the set of equilibrium payoffs (as evaluated at the interim stage) having a lattice structure. Furthermore, the range of equilibrium payoffs converges to those of the deterministic complete information version of the game, in the limit as the incomplete information vanishes. This entails that such incomplete information alone cannot explain the equilibrium selection suggested by experimental evidence. We thank Atila Abdulkadiroglu, Hans Carlsson, Ani Guerdjikova and an anonymous referee for helpful comments. Part of this work was done while Asheim was visiting Cornell University, which hospitality is gratefully acknowledged.     

Observing each other’s observations in a Bayesian coordination game

We study a Bayesian coordination game where agents receive private information on the game’s payoff structure. In addition, agents receive private signals that inform them of each other’s private information. We show, that once agents possess these different types of information, there exists a coordination game in the evaluation of this information. Even though the precisions of both signal types are exogenous, the precision with which agents forecast each other’s actions in equilibrium turns out to be endogenous. As a consequence, there exist multiple equilibria which differ with regard to the way that agents weight their private information to forecast each other’s actions.     

Uncertain information structures and backward induction

In everyday economic interactions, it is not clear whether each agent’s sequential choices are visible to other participants or not: agents might be deluded about others’ ability to acquire, interpret or keep track of data. Following this idea, this paper introduces uncertainty about players’ ability to observe each others’ past choices in extensive-form games. In this context, we show that monitoring opponents’ choices does not affect the outcome of the interaction when every player expects their opponents indeed to be monitoring. Specifically, we prove that if players are rational and there is common strong belief in opponents being rational, having perfect information and believing in their own perfect information, then, the backward induction outcome is obtained regardless of which of her opponents’ choices each player observes. The paper examines the constraints on the rationalization process under which reasoning according to Battigalli’s (1996) best rationalization principle yields the same outcome irrespective of whether players observe their opponents’ choices or not. To this respect we find that the obtention of the backward induction outcome crucially depends on tight higher-order restrictions on beliefs about opponents’ perfect information. The analysis provides a new framework for the study of uncertainty about information structures and generalizes the work by Battigalli and Siniscalchi (2002) in this direction.     

A PRIMER ON GLOBAL GAMES APPLIED TO MACROECONOMICS AND FINANCE

This paper shows how to solve global games applied to macroeconomics and finance. We ascertain the roles of public and private information for the determination of a unique equilibrium, and discuss the informative role of market prices. We examine the impact of public information on social welfare, comparing models with and without complementarities at the aggregate level.     

The co-ordination of strategic initiatives within global organizations: the role of global teams

Given the growth in the globalization of organizations, the ability to co-ordinate initiatives of the headquarters and subsidiaries is rapidly becoming a major concern of management. The use of global task teams is explored in this paper to address co-ordination in global networks. A theoretical framework is developed to derive a model for the use of global teams as co-ordinating mechanisms of strategic initiatives in a global organization. The use of teams as a means to intervene between headquarters and subsidiaries is explored, illustrating the unique social capital of global teams. In addition, the potential issues in managing task teams in global organizations are discussed.     

Good neighbors are hard to find: computational complexity of network formation

We investigate the computational complexity of several decision problems in a simple strategic game of network formation. We find that deciding if a player has a strategy that guarantees him a certain payoff against a given strategy profile of the other players is an NP-complete problem. Deciding if there exists a strategy profile that guarantees a certain aggregate payoff is also NP-complete. Deciding if there is a Nash equilibrium in pure strategies which guarantees a certain payoff to each player is NP-hard. The problem of deciding if a given strategy profile is a Nash equilibrium is investigated as well. We would like to thank both referees for valuable corrections and suggestions and one referee in particular for a very detailed and beneficial critique. We thank Colin de la Higuera for fruitful discussions. Support by the French Ministry for Youth, Education and Research, through project SCSHS-2004-04 is gratefully acknowledged.     

信息不完全的信用风险定价模型及其在我国的应用

基于信息不完全的信用风险定价模型与传统的结构化模型和约化模型的最大区别在于它将信息不完全这一前提引入了以信息完全为前提的结构化模型,同时它又考虑了约化模型中强度的优点,引入短期信用风险的度量,成为当前最切合现实的信用风险定价模型。本文认为,应用基于信息不完全的信用风险定价模型来测度信用风险,将具有十分重要的现实意义。     

Robust implementation under alternative information structures

In this paper we consider a model in which agents have complete information about their neighbors and, possibly, incomplete information about the rest of the environment. We consider two different informational frameworks. In the first, agents do not have priors about the relevant characteristics in the rest of the environment. In the second, agents are supposed to have priors about the unknown characteristics. We present a mechanism which implements any social choice correspondence satisfying monotonicity and no veto power in both informational settings for every possible prior thus requiring little knowledge from the point of view of the designer of the information possessed by agents about the environment. The authors wish to thank J. Canals, B. Chakravorty, P. Chander, C. Herrero, G. Orosel, D. Schmeidler, W. Thomson, W. Trockel, F. Vega, A. Villar, T. Yamato and two anonymous referees for helpful comments. The usual disclaimer applies. The first author acknowledges financial support from the Institució Valenciana d’Estudies i Investigació; L.V.I.E. and DGICYT under projects PB/88-0289 and PB/91-0756. The second author acknowledges financial support from DGICYT under project PB/90-0156. A previous version of the paper was written when authors visited (May 1991) the Institute of Mathematical Economics (Bielefeld) to which authors are grateful.