要旨：This paper investigates the impacts of progressive trade openness, technological externalities, and heterogeneity of individuals on the formation of entrepreneurship in a two-country occupation choice model. We show that trade opening gives rise to a non-monotonic process of international specialization, in which the share of entrepreneurial firms in the large (small) country first increases (decreases) and then decreases (increases), with the global economy exhibiting first de-industrialization and then re-industrialization. When countries have the same size, we also show that strong technological externalities make the symmetric equilibrium unstable, generating equilibrium multiplicity, while sufficient heterogeneity of individuals leads to the stability and uniqueness of the symmetric equilibrium.

要旨：地域間格差は、経済学・地域科学における最も大きな関心事項の一つであり、我が国を対象とした実証研究も膨大な数に上る。しかしながらそれらの研究の大半はジニ係数やタイル尺度などの統計量に関する考察か、所得の収束仮説に関する検証を行ったものであり、所得の空間分布に重点を置いて考察した例は極めて少ない。本研究では、我が国の市町村単位の所得データを様々な空間統計手法を用いて分析することにより、地域間の所得格差の動向を従来とは異なる視点から考察することを目的とする。

要旨：空間データに関して、ゾーン設定が分析結果に影響を及ぼす問題は、可変単位地区問題（MAUP）と呼ばれる。MAUPによって空間統計モデルは、パラメータが有意とならなかったり、期待した符号が得られない場合がある。本研究は、空間集計行列を用いることによって、同一の分析対象地域に対してゾーン設定を変更した場合にも、安定したパラメータ推計値が得られる空間統計モデルを提案し、実証分析した結果を報告する。

要旨：In this paper, I construct a two-country general equilibrium model in which oligopolistic firms export goods and undertake cost-reducing R&D investment. Each country imposes tariffs. When the cost of education is sufficiently high, an increase in the tariff rate decreases the level of R&D investment. On the other hand, when the cost of education is sufficiently small, an increase in the tariff rate increases the level of R&D investment.

要旨：This paper analyzes the locations of heterogeneous firms, which are differentiated by indices in the industrial space, when communication externalities generate agglomeration economies. The benefit of a communication decreases as the industrial distance between two firms increases. An interregional communication requires travel cost while an intraregional communication requires no cost. There are also agglomeration diseconomies arising from rise in regional wage rate. We derive three types of stable equilibrium configurations: agglomeration, partial agglomeration, and dispersion. Multiple equilibria of agglomeration and dispersion may exist. Agglomeration is likely to occur when the degree of communication intensity and travel cost are large.

要旨：We examine network formation via bilateral trade agreement (BTA) among three symmetric countries. Each government decides the conclusion of a BTA depending on the differential of ex-post and ex-ante simple sum of real wages in the country. We model the governmental decision in two forms, myopic and farsighted and analyze the effects on the BTA network formation. Firstly, both myopic game and farsighted game never induce star networks as well as the empty network. Second, in most of the cases, the networks resulting from the myopic game coincide those resulting from the farsighted game, but there exist some cases where the two games yield distinct networks.

要旨：This paper argues that a variety of firm specificity supported by sophisticated inter-firm relationships is essential for understanding the mechanics and spatial structure of international production/distribution networks in East Asia. By mapping the two-dimensional fragmentation framework (Kimura and Ando (2005)) into geographical space, the paper proposes the concept of four layers of transactions in production/distribution networks: (i) local, (ii) sub-regional, (iii) regional, and (iv) the world. The concept effectively bridges geographical extensions of production/ distribution networks and the nature of transactions in terms of intra-firm vs. arm's-length as well as technological/managerial conditions. In addition, the paper discusses the implications of such geographical structure of production/distribution networks for technology transfers/spillovers from multinationals to local firms and claims its importance in new development strategies.