Use the payoffs T > R > P > S to make the game to the right the Prisoner's Dilemma. Use each payoff once per player. DO NOT substitute numerical values for the symbolic payoffs.

a. Under what conditions (on ?) is the Grim Trigger Strategy a Nash equilibrium for the repeated version of the game when ? is the expected number of additional periods.

b. Provide intuition for the conditions that you found in (a). Also provide a graph with payoffs on the Y-axis and time on the X-axis that supports you intuition. Note: in deriving your answer you do