A Monopoly’s Revenue 垄断者的收益
u
Total Revenue 总收益
P x Q = TR
u
Average Revenue 平均收益
TR/Q = AR = P
u
Marginal Revenue 边际收益
DTR/DQ = MR
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Government-Created Monopolies
Governments may restrict entry by giving a single firm the exclusive right to sell a particular good in certain markets.
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Natural Monopolies 自然垄断
An industry is a natural monopoly when a single firm can supply a good or service to an entire market at a smaller cost than could two or more firms. 当一个企业能以低于两个或更多企业的成本为整个市 场供给一种物品或劳务时，这个产业就是自然垄断。
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垄断资源
虽然关键资源的排他性所有权是垄断 的潜在原因，但实际上垄断很少产生 于这种原因。
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Monopoly 垄断
Chapter 15
Monopoly 垄断
While a competitive firm is a price taker, a monopoly firm is a price maker.
竞争企业是价格接受者，而垄断企业 是价格制定者。
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政府制造的垄断
政府给予一个企业排他性地出售某种 物品或劳务的权利，限制其他企业进 入市场，从而造成垄断。
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Why Monopolies Arise
Barriers to entry have three sources:
u
u
u
Ownership of a key resource. The government gives a single firm the exclusive right to produce some good. Costs of production make a single producer more efficient than a large number of producers.
u
Monopoly versus Competition
ä Monopoly
• • • • Is the sole producer Faces a downward-sloping demand curve Is a price maker Reduces price to increase sales
ä Competitive Firm
• • • • Is one of many producers Faces a horizontal demand curve Is a price taker Sells as much or as little at same price
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u The
demand curve is downward sloping. u When a monopoly drops the price to sell one more unit, the revenue received from previously sold units also decreases.
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A Monopoly’s Marginal Revenue
A monopolist’s marginal revenue is always less than the price of its good.
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A Monopoly’s Marginal Revenue When a monopoly increases the amount it sells, it has two effects on total revenue (P x Q).
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垄断者的边际收益 垄断者的边际收益总是小于其物品的 价格。
u 需求曲线是向下倾斜的。 u 当垄断者降低价格增加一个单位销量时，
从以前的产品销售中得到的收益也减少。
Monopoly 垄断
u
A firm is considered a monopoly if . . . it is the sole seller of its product. its product does not have close substitutes.
如果一个企业是其产品唯一的卖者，而 且如果其产品并没有相近的替代品，这 个企业就是垄断者。
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为什么会产生垄断
进入障碍有三个主要来源:
予一个企业排他性地生产某种产 品或劳务的权利。 生产成本使一个生产者比大量生产者更 有效率。
Figure 2 Demand Curves for Competitive and Monopoly Firms
(a) A Competitive Firm’ s Demand Curve Price Price
(b) A Monopolist’ s Demand Curve
Demand
Demand
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Monopoly Resources
Although exclusive ownership of a key resource is a potential source of monopoly, in practice monopolies rarely arise for this reason.
output effect—more output is sold, so Q is higher. u The price effect—price falls, so P is lower.
Government-Created Monopolies 政府制造的垄断
Patent and copyright laws are two important examples of how government creates a monopoly to serve the public interest. 专利和 版权 是政府如何为公共利益制造垄断 的两个重要例子。
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Natural Monopolies 自然垄断
A natural monopoly arises when there are economies of scale over the relevant range of output.
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Why Monopolies Arise
为什么会产生垄断 The fundamental cause of monopoly is barriers to entry. 垄断的基本原因是进入障碍。
垄断者如何作出生产与定价决策
u
垄断与竞争 ä 垄断 • 市场上唯一卖者 • 其需求曲线是向右下方倾斜的 • 价格制定者 • 降低价格才能提高销量 ä 竞争企业 • 是很多生产者当中的一个 • 其需求曲线是水平的 • 是价格接受者 • 在相同价格下想卖多少就卖多少