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arXiv · 2502.05920

Information Design and Full Implementation in Nonatomic Games

Frederic Koessler·Marco Scarsini·Tristan Tomala
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Abstract

This paper studies the implementation of Bayes correlated equilibria in symmetric Bayesian games with nonatomic players, using direct information structures and obedient strategies. The main results demonstrate full implementation in a class of games with negative payoff externalities, such as congestion and Cournot games. Specifically, if the game admits a strictly concave potential in every state, then for every Bayes correlated equilibrium outcome with finite support and rational action distributions, there exists a direct information structure that implements this outcome under all equilibria. When the potential is weakly concave, we show that all equilibria implement the same expected total payoff. Additionally, all Bayes correlated equilibria, including those with infinite support or irrational action distributions, are approximately implemented.

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Frederic Koessler, Marco Scarsini, Tristan Tomala. 2025-02-09. Information Design and Full Implementation in Nonatomic Games. https://arxiv.org/abs/2502.05920

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