Games associated with congestion situations a la Rosenthal (1973) have
pure Nash equilibria. This result implicitly relies on the existence
of a potential function. In this paper we provide a characterization o
f potential games in terms of coordination games and dummy games. Seco
nd, we extend Rosenthal's congestion model to an incomplete informatio
n setting, and show that the related Bayesian games are potential game
s and therefore have pure Bayesian equilibria.