国外博弈论课件lecture19.ppt

June 16, 2003 73-347 Game Theory--Lecture 19 June 16, 2003 Lecture 19 Dynamic Games of Complete Information Dynamic Games of Complete and Imperfect Information Outline of dynamic games of complete information Dynamic games of complete information Extensive-form representation Dynamic games of complete and perfect information Game tree Subgame-perfect Nash equilibrium Backward induction Applications Dynamic games of complete and imperfect information More applications Repeated games Today’s Agenda Review of previous class An abstract game: generalization of the tariff game Repeated games An abstract game: generalization of the tariff game Four players: 1, 2, 3, 4. The timing of the game is as follows. Stage1: Player 1 and 2 simultaneously choose actions a1 and a2 from feasible action sets A1 and A2, respectively. Stage 2:After observing the outcome (a1, a2) of the first stage, Player 3 and 4 simultaneously choose actions a3 and a4 from feasible action sets A3 and A4, respectively. The game ends. The payoffs are ui(a1, a2, a3, a4), for i=1, 2, 3, 4 An abstract game: informal game tree Backward induction: solve the smallest subgame Backward induction: back to the root Backward induction: back to the root Tariffs and imperfect international competition (2.2.C of Gibbons) Two identical countries, 1 and 2, simultaneously choose their tariff rates, denoted t1, t2, respectively. Firm 1 from country 1 and firm 2 from country 2 produce a homogeneous product for both home consumption and export. After observing the tariff rates chosen by the two countries, firm 1 and 2 simultaneously chooses quantities for home consumption and for export, denoted by (h1, e1) and (h2, e2), respectively. Market price in two countries Pi(Qi)=a–Qi, for i=1, 2. Q1=h1+e2, Q2=h2+e1. Both firms have a constant marginal cost c. Each firm pays tariff on export to the other country. Tariffs and imperfect international competition This model fits the abstract model. Country 1 and 2 are player 1