要旨：There is increasing empirical evidence that vertical product differentiation is an important determinant of international trade. However, the economic literature so far has solely focused on the case in which quality trade stems from differences between countries. No studies investigate the role of quality trade between similar economies. This paper first develops a simple theoretical trade model that includes vertical product differentiation in a heterogeneous-firm framework. The model yields three main predictions for trade between similar economies. First, exported goods are of higher quality than goods sold on the domestic market. Second, larger economies have on average higher export qualities compared with smaller economies. Third, with increasing trade costs higher quality goods are exchanged. For all three effects, strong empirical support is found using detailed export trade data of the United States and 15 European Union countries.

要旨：This paper aims to address the effects of congestion externalities in a new economic geography context. Our model is the same as the standard CP model except for the assumption that per-unit interregional transport cost depends on total volume of shipped varieties. As a result of the endogeneity of per-unit transport cost, we have some features of agglomeration and dispersion equilibria that are not evident from the standard models. A welfare analysis focuses on a second best problem so that a market still can take a part in generating agglomeration economies. That is, we investigate the relationship between the congestion externalities and the second best unit tax of shipped goods given firm's monopolistic pricing. If skilled workers are nearly agglomerated in one region, the interregional congestion externalities should not be fully internalized regardless of the level of transport technology. In an evenly dispersed economy, however, the second best tax can be larger than the congestion externalities if the level of transport technology is low.

要旨：Using a simple North-South trade model with vertically related markets, we show that a North downstream firm may have an incentive to strategically utilize technology spillovers to a local rival caused by foreign direct investment (FDI). Whether the North firm invests in the South depends on the South firm's capacity to absorb the North technology. FDI arises only if the capacity is medium. Technology spillovers through FDI may benefit all producers and consumers. Our analysis also suggests that very tight intellectual property rights protection in the South may benefit neither the North nor the South, because it "discourages" FDI.

要旨：We construct a framework of endogenous growth and new economic geography models in which industries with vertical linkages grow and agglomerate in a limited number of countries. Using this framework, we consider the outcomes of an R&D subsidy game among countries in the world economy where globalization proceeds. When transaction costs are higher, less industrialized countries are more eager to attract industries with vertical linkages. To prevent the industries from relocating, more industrialized countries choose much higher R&D subsidies. As a result, the industries never relocate and the economy-wide growth rate is very high. When transaction costs decrease, countries are less willing to host industries with vertical linkages. R&D subsidy competition becomes less intensive, and so the industries are more likely to relocate. The economy-wide growth rate fluctuates and decreases on average.

要旨：We consider location choice of Cournot oligopolist in two segmented markets with intrinsic different production cost function and entry cost. We establish they insufficiently (excessively) locate in the market with low production cost if the entry cost in the market with high production cost is (not) relatively higher.

要旨：This theoretical paper investigates whether entering a spoke or a rim route of an incumbent's hub-spoke network is preferable for entrants. The spoke market size is generally larger than the rim market size. The scales of demand for the connecting and direct routings in the rim market are different. Passengers differentiate flights of carriers. Focusing on these characteristics on the demand side, we demonstrate that it is more profitable to enter the spoke route (the rim route) when the scale of demand for the connecting route (the direct route) is comparatively larger. However, this is not always the case. We also find interesting cases where entering a route with a smaller scale of demand is comparatively profitable. Furthermore, we find that entry on the spoke route is always socially preferable.

要旨：This paper proposes a model of learning about a game. Players initially have little knowledge about the game. Through playing the identical game repeatedly, each player not only learns which action to choose but also constructs his personal view on the game. The model is studied using a hybrid payoff matrix of the prisoner's dilemma and coordination games. Results of computer simulations show (1) when all the players are slow in learning the game, they have only a partial understanding of the game, but may enjoy higher payoffs than the cases with full or no understanding of the game; (2) when one of the players is quick in learning the game, he obtains a higher payoff than the others. However, all of them can receive lower payoffs than the case where all the players are slow learners.