《国际经济学》教师手册及课后习题答案（克鲁格曼第六版）imch.docx

《国际经济学》教师手册及课后习题答案（克鲁格曼，第六版）imch ; HAPTER 6ECONOMIES OF SCALE, IMPERFECT COMPETITION, AND INTERNATIONAL TRADEChapter Organization Economies of Scale and International Trade: An Overview Economies of Scale and Market Structure The Theory of Imperfect CompetitionMonopoly: A Brief ReviewMonopolistic CompetitionLimitations of the Monopolistic Competition Model Monopolistic Competition and TradeThe Effects of Increased Market SizeGains from an Integrated Market: A Numerical Example Economies of Scale and Comparative Advantage The Significance of Intraindustry TradeWhy Intraindustry Trade MattersCase Study: Intraindustry Trade in Action: The North American Auto Pact DumpingThe Economics of DumpingCase Study: AntiDumping as ProtectionReciprocal DumpingThe Theory of External EconomiesSpecialized Suppliers Labor Market Pooling Knowledge Spillovers External Economies and Increasing Returns External Economies and International TradeExternal Economies and the Pattern of Trade Trade and Welfare with External Economies Box: Tinseltown Economics Dynamic Increasing Returns Summary35Appendix: Determining Marginal RevenueCHAPTER OVERVIEWIn previous chapters, trade between nations was motivated by their differences in factor productivity or relative factor endowments. The type of trade which occurred, for example of food for manufactures, is based on comparative advantage and is called interindustry trade. This chapter introduces trade based on economies of scale in production. Such trade in similar productions is called intraindustry trade, and describes,for example, the trading of one type of manufactured good for another type of manufactured good. It is shown that trade can occur when there are no technological or endowment differences, but when there are economies of scale or increasing returns in production.Economies of scale can either take the form of 1) external economies whereby the cost per unit depends on the size of the industry but not necessarily on the size of the firm; or as 2) internal economies, whereby the production cost per unit of output depends on the size of the individual firm but not necessarily on the size of the industry. Internal economies of scale give rise to imperfectly competitive markets, unlike the perfectly competitive market structures that were assumed to exist in earlier chapters. This motivates the review of models of imperfect competition, including monopoly and monopolistic competition. The instructor should spend some time making certain that students understand the equilibrium concepts of these models since they are important for the justification of intraindustry trade.In markets described by monopolistic competition, there are a number of firms in an industry, each of which produces a differentiated product. Demand for its good depends on the number of other similar products available and their prices. This type of model is useful for illustrating that trade improves the trade-off between scale and variety available to a country. In an industry described by monopolistic competition, a larger market -- such as that which arises through international trade -- lowers average price (by increasing production and lowering average costs) and makes available for consumption a greater range of goods. While an integrated markets also supports the existence of a larger number of firms in an industry, the model presented in the text does not make predictions about where these industries will be located.It is also interesting to compare the distributional effects of trade when motivated by comparative advantage with those when trade is motivated by increasing returns to scale in36production. When countries are similar in their factor endowments, and when scale economies and product differentiation are important, the income distributional effects of trade will be small. You should make clear to the students the sharp contrast between the predictions of the models of monopolistic competition and the specific factors and Heckscher-Ohlin theories of international trade. Without clarification, some students may find the contrasting predictions of these models confusing.Another important issue related to imperfectly competitive markets is the practice of price discrimination, namely charging different customers different prices. One particularly controversial form of price discrimination is dumping, whereby a firm charges lower prices for exported goods than for goods sold domestically. This can occur only when domestic and foreign markets are segmented. While there is no good economic justification for the view that dumping is harmful, it is often viewed as an unfair trade practice.The other type of economies of scale, external economies, has very different economic implications than internal economies. Since external economies of scale occur at the industry level rather than the firm level, it is possible for。