A repeated game is an extensive-form game formed by playing a specified stage game more than once.
In a finitely repeated game, the number of stages is fixed. In an infinitely repeated
game, future stage payoffs are commonly weighted by a
discount factor 
,
giving a payoff proportional to
 |
where 
is the stage payoff at time 
. Because actions can depend on the observed history, rewards
and punishments can support equilibria unavailable in the one-shot game; this phenomenon
is formalized by the folk theorem.
