Approachability in population games

This paper reframes approachability theory within the context of population games. Thus, whilst a player still aims at driving her average payoff to a predefined set, her opponent is no longer malevolent but instead is extracted randomly at each instant of time from a population of individuals choos...

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Main Authors: Bauso, D, Norman, T
Format: Journal article
Language:English
Published: American Institute of Mathematical Sciences 2020
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author Bauso, D
Norman, T
author_facet Bauso, D
Norman, T
author_sort Bauso, D
collection OXFORD
description This paper reframes approachability theory within the context of population games. Thus, whilst a player still aims at driving her average payoff to a predefined set, her opponent is no longer malevolent but instead is extracted randomly at each instant of time from a population of individuals choosing actions in a similar manner. First, we define the notion of 1st-moment approachability, a weakening of Blackwell's approachability. Second, since the endogenous evolution of the population's play is then important, we develop a model of two coupled partial differential equations (PDEs) in the spirit of mean-field game theory: one describing the best-response of every player given the population distribution, the other capturing the macroscopic evolution of average payoffs if every player plays her best response. Third, we provide a detailed analysis of existence, nonuniqueness, and stability of equilibria (fixed points of the two PDEs). Fourth, we apply the model to regret-based dynamics, and use it to establish convergence to Bayesian equilibrium under incomplete information.
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spelling oxford-uuid:84f5598d-83b7-4df0-9006-4c3550bf28102022-03-26T21:54:23ZApproachability in population gamesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:84f5598d-83b7-4df0-9006-4c3550bf2810EnglishSymplectic ElementsAmerican Institute of Mathematical Sciences2020Bauso, DNorman, TThis paper reframes approachability theory within the context of population games. Thus, whilst a player still aims at driving her average payoff to a predefined set, her opponent is no longer malevolent but instead is extracted randomly at each instant of time from a population of individuals choosing actions in a similar manner. First, we define the notion of 1st-moment approachability, a weakening of Blackwell's approachability. Second, since the endogenous evolution of the population's play is then important, we develop a model of two coupled partial differential equations (PDEs) in the spirit of mean-field game theory: one describing the best-response of every player given the population distribution, the other capturing the macroscopic evolution of average payoffs if every player plays her best response. Third, we provide a detailed analysis of existence, nonuniqueness, and stability of equilibria (fixed points of the two PDEs). Fourth, we apply the model to regret-based dynamics, and use it to establish convergence to Bayesian equilibrium under incomplete information.
spellingShingle Bauso, D
Norman, T
Approachability in population games
title Approachability in population games
title_full Approachability in population games
title_fullStr Approachability in population games
title_full_unstemmed Approachability in population games
title_short Approachability in population games
title_sort approachability in population games
work_keys_str_mv AT bausod approachabilityinpopulationgames
AT normant approachabilityinpopulationgames