要旨：Constructing a two-country oligopolistic model where each oligopolist's production is subject to external economies of scale, this paper characterizes the trading equilibria, and explores trade patterns and gains from trade in each possible equilibrium. Whether a country exports the increasing returns good and gains from trade highly depends on the relative magnitude of increasing returns to the number of oligopolists, i.e., market power in the oligopolistic sector. It is carefully studied how these two fundamentals interactively determine the equilibrium trade pattern and the distribution of trade gains.

要旨：ファンと呼ばれる消費者が企業間の競争において持つ存在意義を空間競争モデルによって明示的に分析する。近い製品特性をもった製品同士が微妙に差別化された状況で価格競争をしのぎ合いながら、密集した財のバラエティを実現している状況がある。例えば、緑茶飲料などはごくわずかな差異を持った製品が数多く存在する。このような密集した多様性が競争から生み出される要因はファンと呼ばれる消費者にあると考えられる。本研究ではそれらの消費者に焦点を当てて、彼らが市場において果たす役割について分析する。具体的には、ファンの存在をホテリング線分上に明示的に導入した空間競争モデルを考え、企業数2 の2 段階空間競争モデルで、より近い立地で製品特性と価格の競争をランダムにおこなう均衡が得られることを示す。

要旨：This paper establishes the existence and efficiency of equilibrium in a local public goods economy with spatial structures by formalizing Hamilton's (1975 Urban Studies) elaboration of Tiebout's (1956 JPE) tale. We use a well-known equilibrium concept from Rothschild and Stiglitz (1976, QJE) in a market with asymmetric information, and show that Hamilton's zoning policy plays an essential role in proving existence and efficiency of equilibrium. We use an idealized large economy following Ellickson, Grodal, Scotchmer and Zame (1999, Econometrica) and Allouch, Conley and Wooders (2004). Our theorem is directly applicable to the existence and efficiency of a discrete approximation of mono-or multi-centric city equilibrium in urban economics with commuting time costs even if we allow existence of multiple qualities of (collective) residences, when externalities due to traffic congestion are not present.

要旨：This paper argues that currently advanced, aging economies experienced a qualitative change in the role of public education during the process of industrialization. In the early stages of the Industrial Revolution, public education was regarded as a duty that regulated child labor and thereby discouraged childbirth. As these economies developed and the population aged, younger generations came to view public education as a right, whereas older generations desirous of other public services became more politically influential. The eventual policy bias in favor of the elderly placed a heavier education burden on the young, inducing them to have fewer children. This vicious cycle between population aging and the undersupply of public education may have decelerated economic growth in the last few decades.