微观经济学课件chapter08章节

一比一的地图是没有任何意义的！ 琼.罗宾逊不完全竞争理论（1933） 故曰：“天下熙熙，皆为利来；天下壤壤，皆为利往。” 司马迁（BC145-BC87年?）“史记-货殖列传”,市场结构的基本思想和概念,市场的坐标系 分析市场的四个七个坐标轴 现实市场与理论市场的关系 存在和多样性 分析的基本工具 市场均衡的黄金规则 期均衡的变化 基本概念 四种市场结构的关系和演化 均衡价格和产量的形成,市场结构划分的依据,决定市场结构的七大要素 参与者：市场参与者的数量和分布 商品差别性：商品之间的可替代程度 市场壁垒：市场进入和退出的难易程度 信息完备性：参与者之间充分和对称程度 交易成本：四种成本 产品可分性：捆绑销售 交易时滞性：订单和库存,5,市场类型与基本特征,市场类型与基本特征,2019/6/20,6,市场势力与定价行为,市场结构和价格形成 完全竞争市场-参与者价格的接受者 垄断竞争市场-参与者价格的追随者 寡头垄断市场-参与者价格的合谋者 完全垄断市场-参与者价格的制定者 思考的出发点：市场地位决定定价能力,2019/6/20,7,CHAPTER 8 OUTLINE,8.1 Perfectly Competitive Markets 8.2 Profit Maximization 8.3 Marginal Revenue, Marginal Cost, and Profit Maximization 8.4 Choosing Output in the Short Run 8.5 The Competitive Firms Short-Run Supply Curve 8.6 The Short-Run Market Supply Curve 8.7 Choosing Output in the Long Run 8.8 The Industrys Long-Run Supply Curve,PERFECTLY COMPETITIVE MARKETS,The model of perfect competition rests on three basic assumptions: (1) price taking, (2) product homogeneity, and (3) free entry and exit.,Price Taking,Because each individual firm sells a sufficiently small proportion of total market output, its decisions have no impact on market price., price taker Firm that has no influence over market price and thus takes the price as given.,Product Homogeneity,When the products of all of the firms in a market are perfectly substitutable with one anotherthat is, when they are homogeneousno firm can raise the price of its product above the price of other firms without losing most or all of its business.,PERFECTLY COMPETITIVE MARKETS,Free Entry and Exit, free entry (or exit) Condition under which there are no special costs that make it difficult for a firm to enter (or exit) an industry.,When Is a Market Highly Competitive?,Because firms can implicitly or explicitly collude in setting prices, the presence of many firms is not sufficient for an industry to approximate perfect competition. Conversely, the presence of only a few firms in a market does not rule out competitive behavior. Nevertheless, many markets are highly competitive in the sense that firms face highly elastic market demands and relatively easy entry/exit,PROFIT MAXIMIZATION,Do Firms Maximize Profit?,The assumption of profit maximization is frequently used in microeconomics because it predicts business behavior reasonably accurately and avoids unnecessary analytical complications. For smaller firms managed by their owners, profit is likely to dominate almost all decisions. In larger firms, however, managers who make day-to-day decisions usually have little contact with the owners (i.e. the stockholders). In any case, firms that do not come close to maximizing profit are not likely to survive. Firms that do survive in competitive industries make long-run profit maximization one of their highest priorities.,Alternative Forms of Organization, cooperative Association of businesses or people jointly owned and operated by members for mutual benefit.,PROFIT MAXIMIZATION,Nationwide, condos are a far more common than co-ops, outnumbering them by a factor of nearly 10 to 1. In this regard, New York City is very different from the rest of the nationco-ops are more popular, and outnumber condos by a factor of about 4 to 1. What accounts for the relative popularity of housing cooperatives in New York City? Part of the answer is historical. Housing cooperatives are a much older form of organization in the U.S. The building restrictions in New York have long disappeared, and yet the conversion of apartments from co-ops to condos has been relatively slow. The typical condominium apartment is worth about 15.5 percent more than a equivalent apartment held in the form of a co-op. It appears that in New York, many owners have been willing to forgo substantial amounts of money in order to achieve non-monetary benefits.,MARGINAL REVENUE, MARGINAL COST, AND PROFIT MAXIMIZATION, profit Difference between total revenue and total cost.,(q) = R(q) C(q), marginal revenue Change in revenue resulting from a one-unit increase in output.,Profit Maximization in the Short Run,Figure 8.1,A firm chooses output q*, so that profit, the difference AB between revenue R and cost C, is maximized. At that output, marginal revenue (the slope of the revenue curve) is equal to marginal cost (the slope of the cost curve).,/q = R/q C/q = 0,MR(q) = MC(q),MARGINAL REVENUE, MARGINAL COST, AND PROFIT MAXIMIZATION,Demand and Marginal Revenue for a Competitive Firm,Because each firm in a competitive industry sells only a small fraction of the entire industry output, how much output the firm decides to sell will have no effect on the market price of the product. Because it is a price taker, the demand curve d facing an individual competitive firm is given by a horizontal line.,MARGINAL REVENUE, MARGINAL COST, AND PROFIT MAXIMIZATION,Demand and Marginal Revenue for a Competitive Firm,Demand Curve Faced by a Competitive Firm,Figure 8.2,A competitive firm supplies only a small portion of the total o