要旨：This paper investigates how airport congestion pricing affects airline network choices. Highlighting a network that links three congestible public airports and adopting a vertical structure approach, we show that governments can use take-off and landing charges to lead an airline to choose between a hub-spoke (hub) and point-to-point (ptp) network that maximizes social welfare. Given that the hub network uses large aircraft, socially optimal charges set below airport operating costs can lead the airline to choose this network even when the (potential) hub airport is more congested than local airports. When the hub network is chosen, the total subsidy required is almost always smaller than that of a ptp network. This also yields that the hub network is socially preferable from the perspective of subsidies. In addition, asymmetric congestion degrees and complementary relationships among the airports can result in the optimal charges of some airports to be positive.

要旨：City size distributions are known to approximately follow Zipf’s law, or more generally a common power law (CPL), across many countries. The most popular explanation for this regularity has been given by random growth models (e.g., Gabaix, 1999; Duranton, 2006, Rossi-Hanseberg and Wright, 2007), in which the power law results from the common iid growth rate of all cities. Since each subsample of cities has exactly the same properties, it also follows the same power law asymptotically without any role played by geography. The objective of the present paper is to establish counter-evidence from the US and Japan that the geography does indeed matter for CPL to hold among different regions and countries. Specifically, we show that random subsamples of cities taken from geographically connected regions are significantly more consistent with CPL than fully random subsamples. Furthermore, the sets of cities in economically meaningful regions (based on interregional trade) are even more significantly consistent with CPL. Finally, we present preliminary evidence that our finding is consistent with a class of central place models (Hsu, 2013, Akamatsu et al., 2013) in which sizes and locations of cities are determined through the spatial coordination of many industries subject to different degrees of scale economies.

要旨：This paper presents analyses of how the externality of environmental damage affects the equilibrium properties of a simple overlapping generations model with multiple regions. Simulation results show that the government's environmental policy decreases capital accumulation. When the government imposes an environmental tax on the urban sector, such a policy decreases the urban population ratio to the rural but increases the total fertility rate.

要旨：This study considers a small parametric uncertainty of migration cost in a rational expectation two region model with increasing returns to scale and migration cost of each period increases in number of migrants. When the stochastic parameter follows a Brownian motion in continuous time with minute variance, imitative equilibrium belief in which behavior of the stochastic model approximately coincides the deterministic model, is uniquely determined dependent on given state variables; then indeterminacy of equilibria of deterministic model diminishes. However, this result critically depends on the assumption of Brownian motion and it does not hold when we suppose different stochastic process without either of two important characteristics of Brownian motion: infinite length of sample path and continuity.

【応用ミクロ経済学ワークショップと共催】

【応用ミクロ経済学ワークショップと共催】