A general equilibrium analysis of the effects of the formation of customs union on the member countries and non-member countries under imperfect competition

在本研究项目中，我考察了贸易国为形成自由贸易区和关税同盟而进行的政策调整过程中的一些方面。在分析中引入了不完全竞争市场。首先，在一个国际寡头垄断的两国、两种商品、任意多种生产要素贸易模型中，分析了关税和配额对进口国福利的影响，并与自由贸易下的福利水平进行了比较；其次，考察了对寡头垄断中间投入市场征收的关税和配额的等价性。我们重点研究了古诺-纳什均衡，并表明结果取决于经济结构参数的值、最终产品需求的价格弹性和中间投入之间的替代弹性。这一分析可以直接推广到关税同盟的树形国家模型，在该模型中，进口两种中间产品的国家与其中一个贸易国形成关税同盟。接下来，我研究了数量限制水平的变化对国内企业行为和进口国福利的影响。结果表明，前人基于线性需求、不变弹性需求、战略替代等的结果都是特例。我现在正在研究一个问题：一个国家与哪个伙伴结成关税同盟更可取，一个市场不完全竞争的国家还是一个市场完全竞争的国家？

In this research project, I investigated some aspects of the process of policy adjustments performed by the trading countries which aim to form free trade areas and customs union. I introduced imperfect competitive markets in the analyses. The framework of the analyses is basically general equilibrium.First, in a two-country, two-good, arbitrary many factor of production trading model in which one market is international oligopoly, I analyzed the effects of a VERs and quotas on the welfare of the importing country and compared the welfare levels with that under free trade.Secondly I examined the equivalence of tariffs and quotas imposed on oligopolistic intermediate input markets. We focus on a Cournot-Nash equilibrium and show that the outcome depends on the values of the structural parameters of the economy, the price elasticity of demand for the final good and the elasticity of substitution between the intermediate inputs. This analysis could be straightforwardly extended to a tree country model of customs union in which a country importing two intermediate goods forms customs union with one of the trading countries.I next studied the effects of a change in the level of quantity restriction on the behavior of the domestic firm and on the welfare of the importing country. It is shown that the results obtained by predecessors based on linear demand, constant elasticity demand, strategic substitutes and so forth all emerge as special cases.I am now studying a following problem : Which partner is more preferable for a country to form a customs union with, a country with imperfectly competitive markets or a country with perfectly competitive markets?