Abstract
Recent advances in mean-field games and its multi-population variants enable large-scale heterogeneous multi-agent systems to be modeled through representative agents and their associated mean-field distributions. However, existing approaches do not explicitly account for uncertainty in the behavior of other populations. To this end, we introduce a new paradigm: risk-averse multi-population mean-field games, where each population optimizes a worst-case expected reward over dynamically feasible ambiguity sets of mean-field flows of a subset of the other populations. Employing an occupation-measure formulation along with tools from set-valued analysis, we establish, under mild assumptions, several theoretical properties of the multi-population game, including the geometric properties of the ambiguity sets and the existence of a novel risk-averse multi-population mean-field equilibrium. Further, we derive contractivity results of the fixed-point operator under entropy regularization and show that it can be utilized to learn the equilibrium. Finally, we propose a risk-averse fictitious-play scheme and show that exploitability decays to zero, despite the additional nonlinearity introduced by the worst-case objective. We report several numerical experiments to illustrate convergence and risk-averse behavior.
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- Open access
- Green open access
Cite this article
APA 7
Jeloka, B., Ganguly, S., & Tsiotras, P. (2026). Beyond Nominal Equilibria: Risk-Averse Multi-Population Mean-Field Games. https://omanscience.com/en/articles/beyond-nominal-equilibria-risk-averse-multi-population-mean-field-games
MLA 9
Jeloka, Bhavini, et al. "Beyond Nominal Equilibria: Risk-Averse Multi-Population Mean-Field Games." https://omanscience.com/en/articles/beyond-nominal-equilibria-risk-averse-multi-population-mean-field-games.
Chicago (author–date)
Jeloka, Bhavini, Siddhartha Ganguly, and Panagiotis Tsiotras. 2026. "Beyond Nominal Equilibria: Risk-Averse Multi-Population Mean-Field Games." https://omanscience.com/en/articles/beyond-nominal-equilibria-risk-averse-multi-population-mean-field-games.
Harvard
Jeloka, B., Ganguly, S. and Tsiotras, P. (2026) 'Beyond Nominal Equilibria: Risk-Averse Multi-Population Mean-Field Games', Available at: https://omanscience.com/en/articles/beyond-nominal-equilibria-risk-averse-multi-population-mean-field-games.
Vancouver
Jeloka B, Ganguly S, Tsiotras P. Beyond Nominal Equilibria: Risk-Averse Multi-Population Mean-Field Games. https://omanscience.com/en/articles/beyond-nominal-equilibria-risk-averse-multi-population-mean-field-games
IEEE
B. Jeloka, S. Ganguly, and P. Tsiotras, "Beyond Nominal Equilibria: Risk-Averse Multi-Population Mean-Field Games," https://omanscience.com/en/articles/beyond-nominal-equilibria-risk-averse-multi-population-mean-field-games.