On the Number and the Composition of Varieties
构建了一个包含非位似偏好和生产率差异的一般均衡模型，分析消费品种的数量与构成，发现人口与劳动效率对收入弹性影响不同，品种构成取决于各最终品的合意性与技术可行性，且均衡结果可能非最优。
I propose a simple general equilibrium model with nonhomothetic preferences and productivity differences and analyse the number and the composition of varieties in consumption. I obtain the following three results. First, population and labour efficiency have different roles in the income elasticity of demand, thus having different impacts on the number of final goods. Second, given the number of final goods, the composition of varieties is determined by the relative importance of desirability and technological feasibility of each final good. Finally, the equilibrium number and composition of final goods may not necessarily be the same as the optimal ones. Copyright © The Author(s). Journal compilation © Royal Economic Society 2009.