Equilibria in Logit Models of Social Interaction and Quantal Response Equilibrium

HERO WP 2023/1: John K. Dagsvik

Abstract

The Quantal Response Equilibrium (QRE) extends the notion of Nash equilibrium in game theory to a corresponding stochastic equilibrium model. In QRE models, perfectly rational expectations equilibrium embodied in mixed strategy Nash equilibrium is replaced by an imperfect, or noisy, rational expectations equilibrium. An important subclass of QRE is the logit models of social interaction. It is known that at least one equilibrium exists in QRE models, but it is not known if, and when, there exist several equilibria. In this paper we discuss cases when unique- or several equilibria exist in two-persons multinomial logit QRE models. Second, we consider the equilibria in multinomial models with social interaction. Third, we discuss corresponding dynamic games and stability. Finally, we consider several examples.

JEL-Classification: C02; C25; C62; C72; C73

Keywords: Stochastic game theory, Logit QRE, Logit models with social interaction, Multiple equilibria

ISBN: 978-82-7756-275-9

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Publisert 9. mars 2023 12:40 - Sist endret 9. mars 2023 12:53