2025/02/27 by Konczer, Jozsef
#62C20 #68T37 #91A35 (Primary) 91A10 #91B06 (Secondary) #FOS: Computer and information sciences #FOS: Economics and business #G.3 #I.2.11 #J.4 #Machine Learning (stat.ML) #Theoretical Economics (econ.TH)
paper · doi:10.48550/arxiv.2503.01889
This paper introduces a framework for finite non-cooperative games where each player faces a globally uncertain parameter with no common prior. Every player chooses both a mixed strategy and projects an emergent subjective prior to the uncertain parameters. We define an "Extended Equilibrium" by requiring that no player can improve her expected utility via a unilateral change of strategy, and the emergent subjective priors are such that they maximize the expected regret of the players. A fixed-point argument -- based on Brouwer's fixed point theorem and mimicking the construction of Nash -- ensures existence. Additionally, the "No Fictional Faith" theorem shows that any subjective equilibrium prior must stay non-concentrated if the parameter truly matters to a player. This approach provides a framework that unifies regret-based statistical decision theory and game theory, yielding a tool for handling strategic decision-making in the presence of deeply uncertain parameters.