要旨：In this paper, urban land development problem is considered, that is, whether the landowner should construct a building at present for sale in the future with considering the uncertainty of building price. Uncertainty of building price is characterized by possibility distribution to reflect the potential how much the building price will be in the future, which is a kind of likelihood to show similarity between the predicted future situation and the samples appeared in the past time. Two focus points, called active focus point and passive focus point are introduced for balancing satisfaction and plausibility to show which values should be considered for making decision with possibilistic information. Different types of investors, such active one, passive one and more easily satisfied one are considered. The proposed model provides novel insights into individual investment behavior of urban land development in the real world and also some useful regulatory policy for urban land development.

要旨：In Japan, some existing inefficiency in urban land use is related with the land ownership issue, while in China, the succeeded economic reforms have not yet reached the field of the public land ownership. With regard to these problems of land ownership in the real world, most urban economic theories seem still at an early stage, which consider land ownership only in a very simple way. In this paper, I attempt to investigate the land ownership problem in more detail using a few of microeconomic principles, and to compare the public and private land ownerships from the viewpoint of urban residents' welfare.

要旨：Using the spatial price discrimination framework of Hamilton, Thisse, and Weskamp (1989), we investigate the relationship between the locations of firms and the ability to collude. Chang (1991) discussed a mill pricing model and showed that cartel stability increases in the distance between duopolists; thus the most stable cartel is achieved by the maximal distance. In contrast to Chang (1991), we find that the agglomeration at the central point is the most stable location for the cartel in the price-setting model when the number of the firms is two or three. In the case of more than three firms, the central agglomeration is never becomes the most stable location. In the case of four firms, the following location pattern yield the most stable cartel: two firms locate at the one edge of the linear city, and the other two firms locate at the opposite edge.

要旨：完全競争市場では、一物一価が成立し、どのようなタイプ市場（商品に価格を付けて公開するか、ひそかに買い手を探索するかなど）を供給者が選択しようとも、超過利益を享受することはできない。不完全な不動産市場において、品質調整済み不動産の一物一価は成立しない。すなわち、無裁定価格が無数存在する。不完全な市場では、供給者がどのようなタイプ市場を選択するかによって、供給者が獲得する超過利益が異なる可能性がある。供給者の売却方法の選択は、自己の期待利潤を極大にするように行なう。売却方法としては、①売り希望価格を提示し物件を公開し、販売する（定価市場または物件登録市場）、②独自で買い手を探索し、交渉を行なう（交渉市場）、および③オ－クションを行なうなどがある。本報告では、不完全な不動産市場において上記タイプの市場のうち供給者がどのようなタイプを選択するかにをテ-マとするが、特にその前段階である各タイプの市場における供給者と需要者の戦略、取引価格の決定およびその結果の供給者の期待利益について、交渉理論およびオ－クションの理論を用いながら検討した。また、アウトサイドオプション（交渉相手以外の取引相手を探索するというオプション）を考慮した取引における留保価格を定義して、競争条件について考慮したモデルを構築して議論するのも特徴である。

要旨：In the paper, we consider three tenure modes; owner-owned housing, landlord-owned housing, and tenant-owned housing, and develop a model to capture the impact of the rental externality and tenure security on housing quality. We show that the rental externality and tenure security reduce housing quality, when user’s utilization and owner’s maintenance are independent or substitutes in the theoretical part. That is, both landlord-owned housing and tenant-owned housing have lower quality than owner-owned housing. We investigate empirical tests of the issue, and verify the results that are consistent with the theoretical prediction.

要旨：This paper provides evidence that the division of labour is limited by the extent of the (local) market. We first propose a theoretical model whose main prediction is that scarce occupations are over-represented in large cities. Using census data for French cities, we then provide strong empirical support for this prediction.

要旨：本研究の目的は土地利用規制下にある経済を考え、土地利用規制の変更がオフィスビル開発やオフィスの立地行動にいかなる影響をもたらすかについて競争均衡モデルの枠組みで考える。具体的には、建築基準の程度、建ぺい率規制および容積率規制の変更がオフィスビルの開発行動に変化を与え、オフィスビルの床面積市場を通じたオフィス立地と賃料および地代に与える効果を検討する。