要旨：The effort to lower the space barriers is in the core of what we call economic development, industrial structure transformation, and technological innovation like steam engine, motorcar, radio, TV, telephone, mobile phone etc. Owning and consuming them is not the ultimate purpose they serve. They exist to be used to spatially move human beings, commodities, or information. Human activities to lower spatial barriers, which macro-economics is apt to ignore, are nothing else than the dynamic process of economic development itself. To acquire a limited number and quantity of goods and services, we need to mobilize a set of space overcoming system.

要旨：This paper analyzes empirically the effect of spatial agglomeration of activities on the productivity of firms using French individual firm data from 1996 to 2004. This allows us to control for endogeneity biases that the estimation of agglomeration economies typically encounters. French firms benefit from localization economies, but not from urbanization economies nor from competition effects. The benefits generated by increased sectoral clustering, though positive and highly significant are modest and geographically very limited. The gains from clusters are also quite well internalized by firms in their location choice: we find very little difference between the geography that would maximize productivity gains and the geography actually observed.

【基盤研究(S)「東アジアにおける産業集積および企業連関の新展開と共生的持続性の研究」（研究代表者：平川均（名古屋大学））と共催】 要旨：We develop a general equilibrium model of international trade with heterogeneous firms in which wages are endogenously determined. Trade integration forces the least efficient firms to leave the market and, thereby, affects aggregate productivity and wages. Using US-Canadian trade data, we estimate a system of theory-based gravity equations under the equilibrium constraints generated by the model. Doing so allows us to measure ‘border effects’ and to decompose them into: (i) a ‘pure’ border effect; (ii) relative and absolute wage effects; and (iii) a selection effect. Since wages are endogenously determined and react to changes in trade frictions, our model is well suited to the analysis of counterfactual trade liberalization scenarios. Using the estimated parameters from the gravity equation system, we conduct a counterfactual analysis on the impacts of removing the US-Canadian border on wages, productivity, markups, the share of exporting firms, the mass of varieties produced and consumed, and welfare.

【基盤研究(S)「東アジアにおける産業集積および企業連関の新展開と共生的持続性の研究」（研究代表者：平川均（名古屋大学））と共催】 要旨：This paper discusses how the reform agenda of a government in the labour market may be affected by the structure of the political process. We present a theoretical model in which political instability and political polarisation drives the economy towards an equilibrium with labour market regulation and involuntary unemployment. We empirically test these predictions using a panel dataset of 21 OECD countries for the period 1985-2002. Our preliminary results support our theoretical priors: parliamentary fragmentation and a proportionary electoral system are associated to a higher policy stance in the labour market and long term unemployment.

【応用ミクロ経済学・産業経済学ワークショップと共催】

要旨：This paper provides a theory of the location of firms and, as cities are groups of firms, the emergence of cities. Using a model of equilibrium entry, this paper provides a microfoundation for central place theory and the conditions under which Zipf’s law for cities emerges. Central place theory describes how a hierarchical city system with different layers of cities serving different sized market areas forms from a uniformly populated space. Zipf’s law for cities, that is, the size distribution of cities following the Pareto distribution with a tail index close to 1, is a robust empirical regularity. In the model, the main force driving the size difference of cities is the tradeoff between transportation cost and scale economies, which differs across goods due to different fixed costs of production. Since a central place hierarchy also implies a hierarchy of firms, Zipf’s law for firms is also approximated. The theory is also consistent with a newly discovered empirical regularity, the number-average-size rule, which is a log-linear relationship between the number of cities and the average size of cities where an industry is located.

要旨：Both the term “regional economic integration” and that the economics of integration developed as a sub-branch of international economics are used lavishly in the case of domestic inter-regional analysis in China currently on one hand. While the new economic geography developed as a framework of spatial analysis is flooding the classrooms of economics at major universities in mainland China, on the other hand. Based on the analysis of the peculiarities of the multi-layered regions and deep governmental involvements in both national economy and regional ones extensively, this paper suggests that a clever choice is to combine the both instruments together in analyzing the inter-regional economic relationship of the Chinese economy, considering its complexities and peculiarities being an economy both in the process of institutional transition and industrialization.

要旨：We criticize the theories used to explain the size distribution of cities. They take an empirical fact and work backward to obtain assumptions on primitives. The induced theoretical assumptions on consumer behavior, particularly about their inability to insure against the city-level productivity shocks in the model, are untenable. With either self insurance or insurance markets, and either an arbitrarily small cost of moving or the assumption that consumers do not perfectly observe the shocks to firms' technologies, the agents will never move. Even without these frictions, our analysis yields another equilibrium with insurance where consumers never move. Thus, insurance is a substitute for movement. We propose an alternative class of models, involving extreme risk against which consumers will not insure. Instead, they will move, generating a Frechet distribution of city sizes that is empirically competitive with other models.

【応用ミクロ経済学・産業経済学ワークショップと共催】