Treating the book international trade theory by dixit and norman as a benchmark , this paper describes the three changes facing modern international trade theory , explores the comparative advantages of the dual general equilibrium approach in deepening the international trade theory , and shows the causes and process that this approach has been growing into a mainstream analytic paradigm from a special analytic technique 摘要本文以迪克西特与诺曼合著的《国际贸易理论》一书为参照，分析了现代贸易理论所面临的三种挑战，探讨了对偶性一般均衡分析方法在应对这些实践挑战与深化国际贸易理论的比较优势，并且揭示了对偶性一般均衡分析方法由一种特殊的分析技术成长为国际贸易研究中的主流分析范式的过程与原因。
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But my focus was specially laid on the decision - making of investment under uncertainty and with competition , i first . extend the basic model of dixit & pindyck ' s by allowing the relevant parameter to be a random variable , then proposed an numerical example to show how to solve this model , i gave the algorithm and did the comparative static analysis , finally i developed a model of duopoly under uncertainty , considering the competition between the firms explicitly , using roa , i calculated the two firm ' s values respectively when they take different roles - to be leader or follower , and then checked the possible equilibriums 本文的重点是考察在同时存在不确定性和竞争的情况下，如何用实物期权的理论估算投资项目的价值，为此，文中发展了两个模型，第一个模型是对dixit & pindyck的模型的扩展，它通过一个相关的随机变量来考察竞争对项目价值的影响，但没有考虑企业间的相互博弈，文中给出了一个例子详细地说明了该模型的求解并做了敏感性分析；第二个模型是一个不确定情况下的双寡头模型，文中给出了用实物期权方法计算的两企业在处于领导者和跟随者两种不同境况时的价值，并将企业间的相互博弈考虑在内，考察了可能的均衡状态。
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But in the second phase , all of these theories can still be categorized into 4 kinds : dynamic comparative advantage theories , such as the new factors theories by baldwin and kenen , the life - cycle theory by vernon and hirsh , etc ; intra - industry trade theories such as product differentiation model by stiglitz and dixit , the strategy trade theory by spense , brander and krugman , and so on ; the endogenous trade theory such as technology overflow effect and learning curves theory by romer and krugman , the neo - classic trade theory by tucher and young , and the like ; and the competitive advantage theory by michael porter 在这一时期,经济学家们提出了形形色色的理论,出现了“百家争鸣”局面。基本上可以归于以下四大类型:一是动态的比较优势理论;二是产业内贸易理论;三是内生国际贸易理论;四是竞争优势理论。各个阶段的比较优势理论有其时代特点,但一个共同点是:比较优势始于成本差异,并一直没有突破成本差异,而不考虑产品的附加值。
