A Unifying Approach to Existence of Nash Equilibrium.

An approach initiated in [4] is shown to unify results about the existence of (1) Nash equilibria in games with at most countably many players, (2) Cournot-Nash equilibrium distributions for large, anonymous games, and (3) Nash equilibria (both mixed and pure) for continuum games. A new, central notion of mixed externality is developed for this purpose.