Approximated cooperative equilibria for games played over event trees

We consider the class of stochastic games played over event trees. We suppose that the players agree to cooperate and maximize their joint payoff. To sustain cooperation over the event tree, we use trigger strategies. As we are dealing with a finite horizon, it is known that deviation from cooperation in the last stage cannot be deterred, as there is no possibility for punishing the deviator(s). Consequently, we focus on epsilon equilibria. We prove the existence of an epsilon-perfect equilibrium.