【正文】 ?存在由高于邊際成本的價格加成引起的標(biāo)準(zhǔn)無謂損失。 ?辯護(hù)者還認(rèn)為，廣告加劇了競爭，為顧客提供了更多的產(chǎn)品和價格。 2023 by Harcourt, Inc. Monopolistic Competition and the Welfare of Society ? The productvariety externality: ?Because consumers get some consumer surplus from the introduction of a new product, entry of a new firm conveys a positive externality on consumers. ? The businessstealing externality: ?Because other firms lose customers and profits from the entry of a new petitor, entry of a new firm imposes a negative externality on existing firms. Harcourt, Inc. items and derived items copyright 169。 2023 by Harcourt, Inc. 壟斷競爭與完全競爭 ? 高于邊際成本的價格加成 ?對一個競爭企業(yè)來說，價格等于邊際成本。 ? 利潤最大化要求邊際收益等于邊際成本。 ?市場已有企業(yè)的產(chǎn)品需求減少，利潤下降。 2023 by Harcourt, Inc. 很多賣者 有許多企業(yè)爭奪同樣的顧客群體。 Harcourt, Inc. items and derived items copyright 169。 ?每個企業(yè)不是價格接受者，而是面臨一條向右下方傾斜的需求曲線。隨著企業(yè)退出： ? 顧客可選擇的產(chǎn)品數(shù)量少了。 2023 by Harcourt, Inc. Monopolistic versus Perfect Competition There are two noteworthy differences between monopolistic and perfect petition—excess capacity and markup. Harcourt, Inc. items and derived items copyright 169。 2023 by Harcourt, Inc. 圖 3. 壟斷競爭和完全競爭 產(chǎn)量 (a) 壟斷競爭企業(yè) (b) 完全競爭企業(yè) 產(chǎn)量 價格 P = MR (需求曲線 ) MC ATC 生產(chǎn)量 有效規(guī)模 價格 需求 MC ATC P = MC 過剩市場能力 邊際成本 價格加成 MR 生產(chǎn)量 = 有效規(guī)模 Harcourt, Inc. items and derived items copyright 169。 Harcourt, Inc. items and derived items copyright 169。 2023 by Harcourt, Inc. Brand Names ?Economists have argued that brand names may be a useful way for consumers to ensure that the goods they are buying are of high quality. ?providing information about quality. ?giving firms incentive to maintain high quality. Harcourt, Inc. items and derived items copyright 169。 ?廣告和品牌的批評者認(rèn)為，企業(yè)用這些方法利用了消費者的缺乏理性，并減少了競爭。 2023 by Harcourt, Inc. 小結(jié) ?壟斷競爭市場有三個特點：許多企業(yè)、差異化的產(chǎn)品以及自由進(jìn)入和退出。 ? They also argue that it impedes petition by implying that products are more different than they truly are. 批評者還認(rèn)為，廣告抑制了競爭。 Harcourt, Inc. items and derived items copyright 169。 ?在長期中，壟斷競爭企業(yè)存在過剩生產(chǎn)能力。 2023 by Harcourt, Inc. The LongRun Equilibrium 長期均衡 Firms will enter and exit until the firms are making exactly zero economic profits. 企業(yè)進(jìn)入或退出的過程一直持續(xù)到市場中的企業(yè)的經(jīng)濟(jì)利潤正好是零時。 2023 by Harcourt, Inc. Monopolistic Competition in the Short Run Shortrun economic profits encourage new firms to enter the market. This: ? Increases the number of products offered. ? Reduces demand faced by firms already in the market. ?Incumbent firms’ demand curves shift to the left. ?Demand for the incumbent firms’ products fall, and their profits decline. Harcourt, Inc. items and derived items copyright 169。 Harcourt, Inc. items and derived items copyright 169。 ?寡頭 ?只有很少賣者，出售相似或相同的產(chǎn)品。 Harcourt, Inc. items and derived items copyright 169。 2023 by Harcourt, Inc. 圖 1. 短期中的壟斷競爭企業(yè) 產(chǎn)量 0 價格 需求 MR 虧損 (b) 企業(yè)虧損 MC ATC 平均 總成本 利潤最小化產(chǎn)量 價格 Harcourt, Inc. items and derived items copyright 169。 ?競爭市場上的自由進(jìn)入使企業(yè)生產(chǎn)平均總成本最小的產(chǎn)量，即企業(yè)的有效規(guī)模產(chǎn)量。 ?但是，管制所有生產(chǎn)差異產(chǎn)品的企業(yè)的管理負(fù)擔(dān)將是巨大的。 2023 by Harcourt, Inc. Advertising 廣告 ? Critics of advertising argue that firms advertise in order to manipulate people’s tastes. 廣告的批評者認(rèn)為，企業(yè)做廣告是為了操縱人們的嗜好。 2023 by Harcourt, Inc. Summary ?A monopolistically petitive marke