This book constitutes the proceedings of the 6th International Symposium on Algorithmic Game Theory, SAGT 2013, held in Aachen, Germany, in October 2013. The 25 papers presented in this volume were carefully reviewed and selected from 65 submissions. They cover various important aspects of algorithmic game theory, such as solution concepts in game theory, efficiency of equilibria and the price of anarchy, computational aspects of equilibria and game theoretical measures, repeated games and convergence of dynamics, evolution and learning in games, coordination and collective action, network games and graph-theoretic aspects of social networks, voting and social choice, as well as algorithmic mechanism design.

The Complexity of Fully Proportional Representation for Single-Crossing Electorates.- New Results on Equilibria in Strategic Candidacy.- Plurality Voting with Truth-Biased Agents.- Reliability Weighted Voting Games.- The Power of Mediation in an Extended El Farol Game.- Friend of My Friend: Network Formation with Two-Hop Benefit.- Load Rebalancing Games in Dynamic Systems with Migration Costs.- Stochastic Congestion Games with Risk-Averse Players.- Congestion Games with Player-Specific Costs Revisited.- Using Reputation Instead of Tolls in Repeated Selfish Routing with Incomplete Information.- Anti-coordination Games and Stable Graph Colorings.- Approximating Multi Commodity Network Design on Graphs of Bounded Pathwidth and Bounded Degree.- Cooperative Equilibria in Iterated Social Dilemmas.- Symmetries of Quasi-Values.- Dividing Connected Chores Fairly.- On Popular Random Assignments.- Scheduling a Cascade with Opposing Influences.- Designing Budget-Balanced Best-Response Mechanisms for Network Coordination Games.- Inefficiency of Games with Social Context.- Copula-Based Randomized Mechanisms for Truthful Scheduling on Two Unrelated Machines.- Imperfect Best-Response Mechanisms.- Pricing Ad Slots with Consecutive Multi-unit Demand.