Multiplicity of Equilibria in the War of Attrition with Two-Sided Asymmetric Information

Fuente: arXiv
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Main Authors: Castillo-Quintana, Martin, Miranda-Romero, Gianfranco
Format: Preprint
Published: 2026
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author Castillo-Quintana, Martin
Miranda-Romero, Gianfranco
author_facet Castillo-Quintana, Martin
Miranda-Romero, Gianfranco
contents The war of attrition with two-sided asymmetric information is a foundational model in political economy, yet it generically admits a continuum of perfect Bayesian equilibria. This paper characterizes the sources of equilibrium multiplicity. We identify conditions on the type distribution that determine which form of multiplicity arises: when the lower limit of the hazard potential -- the integral of the hazard rate normalized by type -- diverges, the free parameter is the relative aggressiveness of strategies; when that limit is finite, the free parameter is the mass of types conceding immediately. We prove that the Amann-Leininger payoff perturbation and the introduction of behavioral types -- two seemingly distinct refinements -- are mathematically equivalent and succeed in selecting a unique equilibrium if and only if the type support is bounded. For unbounded supports, multiplicity persists. These results provide guidance for applied theorists: choosing distributions with bounded support ensures existing refinements deliver unique predictions.
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id arxiv_https___arxiv_org_abs_2603_13634
institution arXiv
publishDate 2026
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spellingShingle Multiplicity of Equilibria in the War of Attrition with Two-Sided Asymmetric Information
Castillo-Quintana, Martin
Miranda-Romero, Gianfranco
Theoretical Economics
The war of attrition with two-sided asymmetric information is a foundational model in political economy, yet it generically admits a continuum of perfect Bayesian equilibria. This paper characterizes the sources of equilibrium multiplicity. We identify conditions on the type distribution that determine which form of multiplicity arises: when the lower limit of the hazard potential -- the integral of the hazard rate normalized by type -- diverges, the free parameter is the relative aggressiveness of strategies; when that limit is finite, the free parameter is the mass of types conceding immediately. We prove that the Amann-Leininger payoff perturbation and the introduction of behavioral types -- two seemingly distinct refinements -- are mathematically equivalent and succeed in selecting a unique equilibrium if and only if the type support is bounded. For unbounded supports, multiplicity persists. These results provide guidance for applied theorists: choosing distributions with bounded support ensures existing refinements deliver unique predictions.
title Multiplicity of Equilibria in the War of Attrition with Two-Sided Asymmetric Information
topic Theoretical Economics
url https://arxiv.org/abs/2603.13634