Sanjari, S.Saldı, NaciYüksel, S.2024-03-082024-03-082023-07-03979-8-3503-2806-6979-8-3503-2807-3978-1-6654-6952-40743-1619https://hdl.handle.net/11693/114413Conference Name: 2023 American Control Conference (ACC)Date of Conference: 31 May 2023 - 02 June 2023We study stochastic mean-field games among finite number of teams each with large finite as well as infinite numbers of decision makers (DMs). We establish the existence of a Nash equilibrium (NE) and show that a NE exhibits exchangeability in the finite DM regime and symmetry in the infinite one. We establish the existence of a randomized NE that is exchangeable (not necessarily symmetric) among DMs within each team for a general class of exchangeable stochastic games. As the number of DMs within each team drives to infinity that is for the mean-field games among teams), using a de Finetti representation theorem, we establish the existence of a randomized NE that is symmetric (i.e., identical) among DMs within each team and also independently randomized. Finally, we establish that a NE for a class of mean-field games among teams (which is symmetric) constitutes an approximate NE for the corresponding pre-limit game among teams with mean-field interaction and large but finite number of DMs.en-USGamesNash equilibriumConference Paper10.23919/ACC55779.2023.101561972378-5861