要旨：Unlike most of the theoretical researches on economic geography, I assume consumers do not necessarily have access to all the varieties in the market, which motivates firms to compete one another for acquiring customers, and investigate the effects of such competition on economic geography. I first extend the general equilibrium model of monopolistic competition in the closed economy by assuming consumers’ limited access to varieties, and then apply it to the model with two regions. I show (1) the core region enjoys more varieties than the periphery, and (2) economic activities may disperse even at low trade costs when the competition for attention is fierce.

【国際経済学セミナーと共催】
要旨：This paper examines the impact of temperature changes on rural-urban migration using a 56km×56km grid cell level dataset covering the whole world at 10-year frequency during the period 1970-2000. We find that rising temperatures reduce rural-urban migration in poor countries and increase such migration in middle-income countries. These asymmetric migration responses are consistent with a simple model where rural-urban earnings differentials and liquidity constraints interact to determine rural-to-urban migration flows. We also confirm these temperature effects using country-level observations constructed by aggregating the grid cell level data. We project that expected warming in the next century will encourage further urbanization in middle-income countries such as Argentina, but it will slow down urban transition in poor countries like Malawi and Niger.

要旨：This paper investigates unit-level monthly dynamics of housing rents through periods of tenancy and vacancy, using a unique panel of rental units in Tokyo through 1996-2017. We find that (i) consistent overall rent stickiness is attributable to the small extensive margin (limited adjustment opportunity) and small intensive margin (rare adjustment at contract renewal stages); (ii) expanded rent gaps from market level during tenancies become small during vacancies; and (iii) rents exhibit time/state dependence during both tenancies and vacancies, while a specific relationship between a long-term tenant and an owner results in a discount during the tenancy.

要旨：When making a location decision, a firm considers only its own trading costs and ignores trading costs paid by trading partner firms. The exclusion of the latter is the source of locational externalities. We examine this locational externality in the Tokyo metropolitan area, using the actual trade networks. Results show (1) we classify what trade patterns involve locational externalities, (2) the ratio of trades involving locational externalities is about 8%, and (3) the transfer of a randomly-chosen 5% of firms to the center of Tokyo can generate external benefits of 0.13-0.21% in the total industry in terms of value added.

要旨：High-speed rail integrates regions and cities, and thus can possibly have significant impacts on the distribution of economic activities. Using the opening and extensions of a high-speed rail, Shinkansen, in Kyushu, Japan, we examine its effects on the distribution of economic activities across urban agglomerations. We focus on changes in land prices and estimate hedonic price equations to conduct a difference-in-difference analysis. We find that the large metropolitan areas gained from the high-speed rail by experiencing increases in land prices, whereas small metropolitan areas located between them lost by experiencing decreased land prices. However, such positive effects are shown to be limited to areas close to Shinkansen stations.

要旨：We study the effect of natural disasters on port level exports. We model the interaction between firms and ports to study how strongly exports from one port are affected by changes in the cost of exporting at neighboring ports. We extend the standard trade model with heterogeneous firms to a multiple port structure where exporting is subject to port specific local transportation costs, port specific fixed export costs and international bilateral trade costs. We show that gravity distortion due to firm heterogeneity is conditional on the comparative advantage at the port level and resulting substitution of exports across ports. We present evidence of the substitution effect using the 2011 Great East Japan Earthquake, indicating that at least 40% of exports was substituted to other ports following the disaster. The substitution effects is strongest in technology intensive product categories, which suggests an interaction between supply chains and domestic trade costs.