Monopoly · 垄断
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| monopoly/məˈnɒpəli/ | 垄断 | lǒng duàn |
| price maker/praɪs ˈmeɪkə/ | 价格制定者 | jià gé zhì dìng zhě |
| marginal revenue/ˈmɑːdʒɪnl ˈrevənjuː/ | 边际收入 | biān jì shōu rù |
| deadweight loss/ˈdedweɪt lɒs/ | 无谓损失 | wú wèi sǔn shī |
| allocatively inefficient/ˈæləkətɪvli ɪnɪˈfɪʃənt/ | 配置无效率 | pèi zhì wú xiào lǜ |
| natural monopoly/ˈnætʃərəl məˈnɒpəli/ | 自然垄断 | zì rán lǒng duàn |
The only game in town
- One water company. One railway. One patent-holding drug maker.
- When a firm is the sole seller of something with no close substitute, the rules change.
- It no longer takes the price — it makes it.
- That is a monopoly 垄断.
镇上唯一的选择
- 一家自来水公司。一条铁路。一个握有专利的药厂。
- 当一家企业是某样没有相近替代品的东西的唯一卖家,规则就变了。
- 它不再接受价格——而是制定价格。
- 这就是垄断(monopoly)。
A price maker with MR below price
- A monopoly is a price maker 价格制定者 — it chooses the price by choosing how much to produce.
- To sell one more unit, it must lower the price on every unit.
- So its marginal revenue 边际收入 is less than the price — the MR curve lies below demand.
边际收入低于价格的价格制定者
- 垄断者是价格制定者(price maker)——通过选择产量来选择价格。
- 想多卖一个单位,它必须把每一个单位的价格都降下来。
- 所以它的边际收入(marginal revenue)低于价格——MR 曲线位于需求之下。
A monopoly is a price maker, which means it: · 垄断是价格制定者,意思是它:
With no rivals, the monopolist picks the point on the demand curve that maximises profit. · 没有对手,垄断者选择需求曲线上使利润最大的点。
For a monopoly, marginal revenue is below the price because it must cut the price on every unit to sell more. · 对垄断者,边际收入低于价格,因为想多卖就得把每个单位的价格都降下来。
Lowering the price on all units makes the extra revenue (MR) smaller than the price. · 给所有单位降价,使额外收入(MR)小于价格。
Find the monopoly outcome
- The monopolist still obeys the rule: produce where $MR = MC$ to get $Q_M$.
- Then go up to the demand curve to read the price $P_M$.
- Because $P_M > MC$, the last unit is worth more to buyers than it costs to make — but the monopolist won't make it.
- Those lost trades are the deadweight loss 无谓损失, so a monopoly is allocatively inefficient 配置无效率.
求出垄断结果
- 垄断者仍遵守规则:在 $MR = MC$ 处生产,得到 $Q_M$。
- 然后向上到需求曲线,读出价格 $P_M$。
- 因为 $P_M > MC$,最后一个单位对买家的价值高于生产成本——但垄断者不会去生产它。
- 这些消失的交易就是无谓损失(deadweight loss),所以垄断是配置无效率(allocatively inefficient)的。
The firm's cost curves · 企业的成本曲线
A monopolist still produces where marginal revenue meets marginal cost — but then charges a higher price off its downward-sloping demand. · 垄断者仍在边际收入与边际成本相遇处生产——但随后按向下倾斜的需求收取更高价格。
Demand is P = 100 − Q, so MR = 100 − 2Q. With MC = 20, what is the monopoly quantity where MR = MC? · 需求是 P = 100 − Q,所以 MR = 100 − 2Q。当 MC = 20 时,MR = MC 处的垄断数量是多少?
Set 100 − 2Q = 20 → 2Q = 80 → Q = 40. · 令 100 − 2Q = 20 → 2Q = 80 → Q = 40。
Using the same demand P = 100 − Q, what price does the monopolist charge at Q = 40? · 用同样的需求 P = 100 − Q,在 Q = 40 时垄断者收取的价格是多少?
Read the price off demand: P = 100 − 40 = 60. Since 60 > MC = 20, there is a deadweight loss. · 从需求读出价格:P = 100 − 40 = 60。因为 60 > MC = 20,存在无谓损失。
A monopoly is allocatively inefficient because at its output: · 垄断配置无效率,因为在它的产量下:
P > MC means the last unit is worth more than it costs, yet it is not made — a deadweight loss. · P > MC 表示最后一个单位的价值高于成本,却没有生产——无谓损失。
Natural monopoly
- A natural monopoly 自然垄断 has such large fixed costs (a water or power network) that one firm serves the whole market at lower average cost than two could.
- Here, competition would waste resources by duplicating the network.
自然垄断
- 自然垄断(natural monopoly)的固定成本极大(自来水或电力网络),一家企业以低于两家的平均成本服务整个市场。
- 在这里,竞争会因重复建设网络而浪费资源。
A market best served by one firm because of huge fixed costs is a ______ monopoly. · 因固定成本极大而由一家企业服务最省的市场,是______垄断。
A natural monopoly (like a water network) has one firm serve everyone at lower average cost. · 自然垄断(如自来水网络)由一家企业以更低平均成本服务所有人。
A monopoly is the sole seller and a price maker, with marginal revenue below price. It sets $Q_M$ where $MR = MC$, then charges $P_M$ off the demand curve. Because $P_M > MC$ it is allocatively inefficient — a deadweight loss. A natural monopoly is cheapest served by one firm.
垄断是唯一卖家、价格制定者,边际收入低于价格。它在 $MR = MC$ 处定出 $Q_M$,再按需求曲线收取 $P_M$。因为 $P_M > MC$,它配置无效率——存在无谓损失。自然垄断由一家企业服务最省。