Trade and the Topography of the Spatial Economy*
构建了一个一般均衡框架，用于分析任何地理表面上的经济活动空间分布，并结合贸易引力与劳动力流动，给出了均衡存在性、唯一性和稳定性的条件。利用美国数据估计了贸易成本、生产率和便利设施的地形，发现地理位置解释了美国收入空间差异的至少20%，并计算了州际公路系统对福利的提升效果。
Abstract We develop a general equilibrium framework to determine the spatial distribution of economic activity on any surface with (nearly) any geography. Combining the gravity structure of trade with labor mobility, we provide conditions for the existence, uniqueness, and stability of a spatial economic equilibrium and derive a simple set of equations that govern the relationship between economic activity and the geography of the surface. We then use the framework to estimate the topography of trade costs, productivities and amenities in the United States. We find that geographic location accounts for at least twenty percent of the spatial variation in U.S. income. Finally, we calculate that the construction of the interstate highway system increased welfare by 1.1 to 1.4 percent, which is substantially larger than its cost.