寡头市场的特征 Characteristics of an oligopoly Market 双头的例子 ◆少数几个卖者提供相似或相同的产品 A Duopoly Example Few sellers offering similar or identical produc 双头是只有两个卖者的寡头。 ◆相互关联的企业 双头是最简单的寡头模型。 Interdependent firms A duopoly is an oligopoly with 悬延成妻那件生产少量产品并把价 only two members. It is the Best off cooperating and acting like a onopolist by producing a small quantity of molest type of oligopoly output and charging a price above marginal cost 双头的例子:水的需求表 双头的例子:价格和供给量 A Duopoly Example: Demand A Duopoly Example: Price and Quantity Supplied ◆在完全竟争的市场中,水的价格等于边际成本即零 The price of water in a perfectly competitive market would be driven to where the marginal cost is zero P= MC E SO Q =120 gallons 在垄断的市场中,价格和数量使垄断者的总利润最 大化。 The price and quantity in a monopoly market would be where total profit is maximized: P=$60 Q= 60 gallons 竞争、垄断和卡特尔 双头的例子:价格和供给量 Competition, Monopolies, and A Duopoly Example: Price and Cartels Quantity Supplied ◆双头可以同意垄断的结果 ◆社会有效率的水的供应量是120加仑,但老断 The duopolists may agree on a 者只供应60加仑。 monopoly outcome. The socially efficie tity of water is 120 ◆勾结 Collusion gallons, but a monopolist would produce only 60 两个企业就生产的数量和收取的价格达成一致 gallons of water. ◆我们预期双头是什么结果呢? produce and the price to charge. So what outcome then could be expected from ◆卡特尔 Cartel 两个企业联合起来,协调行动 The two firms may join together and act in unIson.2 7 寡头市场的特征 Characteristics of an Oligopoly Market ‹ 少数几个卖者提供相似或相同的产品 Few sellers offering similar or identical products ‹ 相互关联的企业 Interdependent firms ‹ 最好是合作，象垄断那样生产少量产品并把价 格定在边际成本之上 Best off cooperating and acting like a monopolist by producing a small quantity of output and charging a price above marginal cost 8 双头的例子 A Duopoly Example 双头是只有两个卖者的寡头。 双头是最简单的寡头模型。 A duopoly is an oligopoly with only two members. It is the simplest type of oligopoly. 9 双头的例子：水的需求表 A Duopoly Example: Demand Schedule for Water Quantity Price Total Revenue 0 $120 $ 0 10 110 1,100 20 100 2,000 30 90 2,700 40 80 3,200 50 70 3,500 60 60 3,600 70 50 3,500 80 40 3,200 90 30 2,700 100 20 2,000 110 10 1,100 120 0 0 10 双头的例子： 价格和供给量 A Duopoly Example: Price and Quantity Supplied ‹在完全竞争的市场中，水的价格等于边际成本即零 The price of water in a perfectly competitive market would be driven to where the marginal cost is zero: P = MC = $0 Q = 120 gallons ‹在垄断的市场中，价格和数量使垄断者的总利润最 大化。The price and quantity in a monopoly market would be where total profit is maximized: P = $60 Q = 60 gallons 11 双头的例子： 价格和供给量 A Duopoly Example: Price and Quantity Supplied ‹社会有效率的水的供应量是120 加仑，但垄断 者只供应60加仑。 The socially efficient quantity of water is 120 gallons, but a monopolist would produce only 60 gallons of water. ‹我们预期双头是什么结果呢? So what outcome then could be expected from duopolists? 12 竞争、垄断和卡特尔 Competition, Monopolies, and Cartels ‹双头可以同意垄断的结果。 The duopolists may agree on a monopoly outcome. ‹勾结 Collusion ‹两个企业就生产的数量和收取的价格达成一致 The two firms may agree on the quantity to produce and the price to charge. ‹卡特尔 Cartel ‹两个企业联合起来，协调行动。 The two firms may join together and act in unison