Economic Theory

, Volume 42, Issue 1, pp 9–37 | Cite as

Enumeration of Nash equilibria for two-player games

  • David Avis
  • Gabriel D. Rosenberg
  • Rahul Savani
  • Bernhard von Stengel
Symposium

Abstract

This paper describes algorithms for finding all Nash equilibria of a two-player game in strategic form. We present two algorithms that extend earlier work. Our presentation is self-contained, and explains the two methods in a unified framework using faces of best-response polyhedra. The first method lrsnash is based on the known vertex enumeration program lrs, for “lexicographic reverse search”. It enumerates the vertices of only one best-response polytope, and the vertices of the complementary faces that correspond to these vertices (if they are not empty) in the other polytope. The second method is a modification of the known EEE algorithm, for “enumeration of extreme equilibria”. We also describe a second, as yet not implemented, variant that is space efficient. We discuss details of implementations of lrsnash and EEE, and report on computational experiments that compare the two algorithms, which show that both have their strengths and weaknesses.

Keywords

Bimatrix game Nash equilibrium Linear programming Complementarity 

JEL Classification

C72 

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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • David Avis
    • 1
  • Gabriel D. Rosenberg
    • 2
  • Rahul Savani
    • 3
  • Bernhard von Stengel
    • 4
  1. 1.School of Computer Science and GERADMcGill UniversityMontrealCanada
  2. 2.Yale Law SchoolNew HavenUSA
  3. 3.Department of Computer Science and DIMAPUniversity of WarwickCoventryUK
  4. 4.Department of MathematicsLondon School of EconomicsLondonUK

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