"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.

Intracranial transplantation of the tumor induced by adenovirus type 12 in Syrian hamster--an experimental brain tumor model

A method of intracranial transplantation of the tumor induced by adenovirus type 12 in syrian hamster has been described. The incidence of intracranial tumor development was 86 (90.5 %) out of 95 animals and the average survival time and tumor size at death were 15.1 days and 4.1 mm in diameter respectively. The consistency of the days of death after intracranial transplantation of the tumor was remarkable. The transplanted tumors developed preferentially at the site of implantation and tumor cell seeding and tumor growing took place rarely along the ventricular system. Glial or lymphoid cell response to the tumor was not observed at any stage after transplantation in surrounding cerebral tissues of the animals. Histomorphologically, no elementary differences were observed between intracranially transplanted tumors and serially transplanted subcutaneous tumors. These facts permit the system to be applied to an experimental brain tumor model as large-scale testing.</p

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

"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.

"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.

Market Size and Entrepreneurship

In order to examine the impacts of market size on entrepreneurship, we estimate a monopolistic competition model that involves entrepreneurial decision by using data on Japanese prefectures. Our results show that a larger market size measured by the population density leads to higher incentive of people to become entrepreneurs. a 10 percent increase in the population density increases the share of people who wish to become entrepreneurs by 2 percent. In contrast, the self-employment ratio is lower in prefectures with higher population density, which suggests that the market size has different impacts on the entrepreneurship in different stages.market size, entrepreneurship, density economies, market expansion

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