Communication Complexity of Correlated Equilibrium with Small Support

Authors Anat Ganor, Karthik C. S.

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Author Details

Anat Ganor
  • Tel Aviv University, Tel Aviv, Israel
Karthik C. S.
  • Weizmann Institute of Science, Rehovot, Israel

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Anat Ganor and Karthik C. S.. Communication Complexity of Correlated Equilibrium with Small Support. In Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 116, pp. 12:1-12:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


We define a two-player N x N game called the 2-cycle game, that has a unique pure Nash equilibrium which is also the only correlated equilibrium of the game. In this game, every 1/poly(N)-approximate correlated equilibrium is concentrated on the pure Nash equilibrium. We show that the randomized communication complexity of finding any 1/poly(N)-approximate correlated equilibrium of the game is Omega(N). For small approximation values, our lower bound answers an open question of Babichenko and Rubinstein (STOC 2017).

Subject Classification

ACM Subject Classification
  • Theory of computation → Communication complexity
  • Theory of computation → Exact and approximate computation of equilibria
  • Correlated equilibrium
  • Nash equilibrium
  • Communication complexity


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