With many semi-anonymous players, the equilibria of simultaneous-move games are "extensively robust." This means that the equilibria survive even if the simultaneous-play assumption is relaxed to allow for a large variety of extensive modifications. Such modification include sequential play with...

This review focuses on properties related to the robustness and stability of Nash equilibria in games with a large number of players. Somewhat surprisingly, these equilibria become substantially more robust and stable as the number of players increases. We illustrate the relevant phenomena...