"Hotelling's Spatial Competition Reconsidered"

Oligopoly models are usually analyzed in the context of two firms anticipating that market outcomes would be qualitatively similar in the case of three or more firms. This is not an exception in the literature on Hotelling's location-then-price competition. In this paper, we show that the main findings in Hotelling's duopoly, brand bunching and the max-min principle of product differentiation no longer hold once three or more firms are allowed to enter the market. That is, oligopolists with three or more firms proliferate brands and neither maximize nor minimize product differentiation.

"Self-organizing Marketplaces"

Dynamics of retail firms in marketplaces is analyzed, assuming that firms compete within a marketplace as well as between marketplaces under monopolistically competition. The number, size, and location of marketplaces or edge cities are analytically obtained, which is hardly done in the previous literature. Furthermore, extending the model to a two-dimensional space, Christaller-Losch system of hexagonal market areas is analytically derived.

Local politics and economic geography

We consider information aggregation in national and local elections when voters are mobile and might sort themselves into local districts. Using a standard model of private information for voters in elections in combination with a New Economic Geography model, agglomeration occurs for economic reasons whereas voter stratification occurs due to political preferences. We compare a national election, where full information equivalence is attained, with local elections in a three district model. A stable equilibrium accounting for both the economic and political sectors is shown to exist. Restricting to an example, we show that full information equivalence holds in only one of the three districts when transport cost is low. The important comparative static is that full information equivalence is a casualty of free trade. When trade is more costly, people tend to agglomerate for economic reasons, resulting in full information equivalence in the political sector. Under free trade, people sort themselves into districts, most of which are polarized, resulting in no full information equivalence in these districts. We examine the implications of the model using data on corruption in the legislature of the state of Alabama and in the Japanese Diet.information aggregation in elections, informative voting, new economic geography, local politics

Local Politics and Economic Geography

We consider information aggregation in national and local elections when voters are mobile and might sort themselves into local districts. Using a standard model of private information for voters in elections in combination with a New Economic Geography model, agglomeration occurs for economic reasons whereas voter stratification occurs due to political preferences. We compare a national election, where full information equivalence is attained, with local elections in a three district model. A stable equilibrium accounting for both the economic and political sectors is shown to exist. Restricting to an example, we show that full information equivalence holds in only one of the three districts when transport cost is low. The important comparative static is that full information equivalence is a casualty of free trade. When trade is more costly, people tend to agglomerate for economic reasons, resulting in full information equivalence in the political sector. Under free trade, people sort themselves into districts, most of which are polarized, resulting in no full information equivalence in these districts. We examine the implications of the model using data on corruption in the legislature of the state of Alabama and in the Japanese Diet.Information aggregation in elections; Informative voting; New economic geography; Local politics

Local politics and economic geography

We consider information aggregation in national and local elections when voters are mobile and might sort themselves into local districts. Using a standard model of private information for voters in elections in combination with a New Economic Geography model, agglomeration occurs for economic reasons whereas voter stratification occurs due to political preferences. We compare a national election, where full information equivalence is attained, with local elections in a three district model. A stable equilibrium accounting for both the economic and political sectors is shown to exist. Restricting to an example, we show that full information equivalence holds in only one of the three districts when transportation cost is low. The important comparative static is that full information equivalence is a casualty of free trade. When trade is more costly, people tend to agglomerate for economic reasons, resulting in full information equivalence in the political sector. Under free trade, people sort themselves into districts, most of which are polarized, resulting in no full information equivalence in these districts. We examine the implications of the model using data on corruption in the legislature of the state of Alabama and in the Japanese Diet.information aggregation in elections; informative voting; new economic geography; local politics

"Estimating Interregional Utility Differentials"

The examination of long-term Japanese data on interregional migration revealed three stylized facts of migration behavior. Based on the facts, we formulated an operational model and estimated interregional utility differentials. We found that the interregional utility differentials have been converging until the late 1970s. We showed that the utility estimates are highly correlated with per capita real income. We also applied the model to interregional migration in the United States and Canada as well as the interindustry movement in Japan and confirmed the model's validity.

"Self-organizing Urban Hierarchy"

We have considered a general equilibrium model with monopolistically competitive markets, in which urban centers are service suppliers to all the agricultural regions as well as to the other urban centers. We have retained the forward and backward linkages of NEG to generate the agglomeration of firms and workers in cities. Our main result is that central places arise endogenously when transport costs take intermediate values.

"Labor Mobility and Economic Geography"

This paper investigates the impact of the heterogeneity of the labor force on the spatial distribution of activities. This goal is achieved by applying the tools of discrete choice theory to an economic geography model. We show that taste heterogeneity acts as a strong dispersion force. We also show that the relationship between the spatial distribution of the industry (the wage differential) and trade costs is smooth and inverted U-shaped. Finally, while Rawlsian equity leads to the dispersion of industry, our analysis reveals that efficiency leads to a solution close to the market outcome, although the latter is likely to involve too much agglomeration compared to the former.

"Spatial Competition in Variety and Number of Stores"

We propose location-then-variety competition for amulti-productandmulti-store oligopoly,in which the number of firms, the number of stores and their location, and the number of varieties are endogenously determined. We show that ascompared to price-then-variety competition, location-then-variety competition with multi-stores yields a much richer set of equilibrium outcomes, such as market segmentation, interlacing, sandwich and enclosure.

"Stability of Spatial Equilibrium"

This paper focuses on externalities between economic agents. We consider spatial dis- tribution of economic activities in a multiregional dynamical system, where regions may be interpreted as clubs, social subgroups, species, or strategies. Our dynamics includes gravity models and replicator dynamics as special cases. Assuming that other variables, such as prices are solved as a function of the population distribution, we analyze both interior and corner equilibria of spatial distribution in a general class of dynamics, including the replicator dynamics and the gravity model. We derive the exact conditions for stable equilibrium and give some interpretations of the stability conditions. We show that interior equilibria are stable in the presence of strong agglomeration economies, but unstable in the presence of strong congestion diseconomies.