Invariance under type morphisms: the bayesian Nash equilibrium

Pintér, Miklós (2011): Invariance under type morphisms: the bayesian Nash equilibrium.

Abstract

Ely and Peski (2006) and Friedenberg and Meier (2010) provide examples when changing the type space behind a game, taking a "bigger" type space, induces changes of Bayesian Nash Equilibria, in other words, the Bayesian Nash Equilibrium is not invariant under type morphisms. In this paper we introduce the notion of strong type morphism. Strong type morphisms are stronger than ordinary and conditional type morphisms (Ely and Peski, 2006), and we show that Bayesian Nash Equilibria are not invariant under strong type morphisms either. We present our results in a very simple, finite setting, and conclude that there is no chance to get reasonable assumptions for Bayesian Nash Equilibria to be invariant under any kind of reasonable type morphisms.

• Item Type: MPRA Paper
• Language: English
• Keywords: Games with incomplete information; Bayesian Nash Equilibrium; Type space
• Subjects: D - Microeconomics > D8 - Information, Knowledge, and Uncertainty > D80 - General; C - Mathematical and Quantitative Methods > C7 - Game Theory and Bargaining Theory > C72 - Noncooperative Games

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