Updated on 2021/12/08

写真a

 
ADACHI, Tsuyoshi
 
Affiliation
Faculty of Political Science and Economics, School of Political Science and Economics
Job title
Associate Professor

Concurrent Post

  • Faculty of Political Science and Economics   Graduate School of Political Science

Degree

  • Waseda University   M.A. in Economics

  • Waseda University   Doctor of Economics

Research Experience

  •  
     
     

    Takasaki City University of Economics Faculty of Economics   Research Associate

Professional Memberships

  •  
     
     

    日本経済学会

 

Research Areas

  • Economic theory

Research Interests

  • メカニズムデザイン

  • 社会的選択理論

  • 公共経済学

  • ゲーム理論

  • ミクロ経済学

Papers

  • Further axiomatizations of Egghe's g-index

    Tsuyoshi Adachi, Takumi Kongo

    JOURNAL OF INFORMETRICS   9 ( 4 ) 839 - 844  2015.10  [Refereed]

     View Summary

    We provide three axiomatic characterizations of Egghe's g-index, which measures a researcher's scientific output based on the number of papers the researcher has published and the number of citations of each of the researcher's papers. We formulate six new axioms for indexes, namely, tail independence (TA), square monotonicity (SM), the cap condition (CC), strong square monotonicity (SSM), increasing marginal citations (IMC), and increasing marginal citations+ (IMC+). Along with the two well-known axioms T1 and T2 (Woeginger, 2008a), the g-index is characterized by (i) T1, T2, TA, SM, and CC, (ii) T1, T2, TA, SSM, and IMC, and (iii) T1, TA, SM, and IMC+. Two out of three characterizations are obtained by adding axioms to our new characterization of the class of indexes satisfying TI, T2, and TA, which are defined as generalizations of the g-index. Thus, the remaining four axioms in our first and second characterizations SM, CC, SSM, and IMC distinguish the original g-index from other related indexes in the class. Furthermore, the independence of our axioms and that of Woeginger's study is shown. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI

  • Extended anonymity and Paretian relations on infinite utility streams

    Tsuyoshi Adachi, Susumu Cato, Kohei Kamaga

    MATHEMATICAL SOCIAL SCIENCES   72   24 - 32  2014.11  [Refereed]

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    We examine the range of anonymity that is compatible with a Paretian social welfare relation (SWR) on infinite utility streams. Three alternative coherence properties of an SWR are considered, namely, acyclicity, quasi-transitivity, and Suzumura consistency. For each case, we show that a necessary and sufficient condition for a set of permutations to be the set of permissible permutations of some Paretian SWR is given by the cyclicity of permutations and a weakening of group structure. Further, for each case of coherence property, we show that the extended Pareto rule is the least element of the class of anonymous Paretian SWRs. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • A natural mechanism for eliciting rankings when jurors have favorites

    Tsuyoshi Adachi

    GAMES AND ECONOMIC BEHAVIOR   87   508 - 518  2014.09  [Refereed]

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    We analyze the problem of a jury that must rank a set of contestants whose socially optimal ranking is common knowledge among jurors who may have friends among the contestants and may, therefore, be biased in their friends' favor. We show a natural mechanism that is finite and complete informational, with no simultaneous moves (i.e., it is solvable by backward induction), which implements the socially optimal ranking with subgame perfect equilibria. (C) 2014 Elsevier Inc. All rights reserved.

    DOI

  • Robust and secure implementation: equivalence theorems

    Tsuyoshi Adachi

    GAMES AND ECONOMIC BEHAVIOR   86   96 - 101  2014.07  [Refereed]

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    This paper shows that in private value environments, strategy-proofness and the rectangular property are necessary conditions for (full) robust implementation (Bergemann and Morris, 2011). As corollaries, we obtain the equivalence between robust and secure implementation (Saijo et al., 2007), the revelation principle for robust implementation, and characterization of double implementation in robust and secure implementation. (C) 2014 Elsevier Inc. All rights reserved.

    DOI

  • Equity and the Vickrey allocation rule on general preference domains

    Tsuyoshi Adachi

    SOCIAL CHOICE AND WELFARE   42 ( 4 ) 813 - 830  2014.04  [Refereed]

     View Summary

    We consider the problem of allocating multiple units of an indivisible good among a group of agents in which each agent demands at most one unit of the good and money payment or receipt is required. Under general preference domains that may contain non quasi-linear preferences, the Vickrey allocation rule is characterized by axioms for equity and continuity without use of efficiency: namely, the Vickrey rule is the only rule that satisfies strategy-proofness, weak envy-freeness for equals, non-imposition, and continuity of welfare.

    DOI

  • First-price auctions on general preference domains: axiomatic characterizations

    Tsuyoshi Adachi, Takumi Kongo

    Economic Theory Bulletin   1 ( 1 ) 93 - 103  2013  [Refereed]

  • The uniform rule with several commodities: A generalization of Sprumont's characterization

    Tsuyoshi Adachi

    JOURNAL OF MATHEMATICAL ECONOMICS   46 ( 6 ) 952 - 964  2010.11  [Refereed]

     View Summary

    This paper considers the problem of allocating multiple divisible commodities among a group of agents with single-peaked preferences. We show that the uniform rule is the only allocation rule that satisfies strategy-proofness, envy-freeness, and same-sidedness: the third axiom is a weak efficiency condition that is equivalent to Pareto efficiency in the single-commodity case. Therefore, this result generalizes the characterization of the uniform rule by Sprumont (1991. Econometrica 59(2), 509-519) in the single-commodity case: it is the only rule satisfying strategy-proofness, envy-freeness, and Pareto efficiency. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

  • A Theory of Civil Conflict and Democracy in Unequal Societies

    Tsuyoshi Adachi, Yasuhiko Nakamura

    Economics Bulletin   8 ( 2 ) 1 - 11  2008  [Refereed]

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Awards

  • 修士課程 研究科長賞(早稲田大学経済学研究科)

    2007  

Research Projects

  • -

  • -

Specific Research

  • 利害関係を持つ審査員団が勝者を選ぶ際の持ち回り決議メカニズムの有効性

    2011  

     View Summary

    本研究は、候補者との間に利害関係を持つ審査員達(ただしその利害関係は客観的には明らかでない)によって審査団が構成されているようなコンテストにおいて、社会的に望ましいランキングが自発的に選ばれるような審査団内での「ランキング決め」の方法(=メカニズム)として、各ランキングと各候補者についてその候補者がそのランキングにふさわしいか否かを審査員達が逐次的に回答していく“持ち回り決議型メカニズム”を提案するものであった。報告者は以下に挙げた2回の国際学会、1回の国内学会、及び1回の国際ワークショップにおいてその研究成果の発表を行った。それらにおける参加者及び討論者との議論を通じて、(1)本研究の成果の応用範囲が体育競技や工芸品の品評会といった狭義のコンテストの枠組みに留まらず、政策目標の順位付けや選挙などの幅広い社会的意思決定に利用できるものであること、(2)提案されたメカニズムでは特定の審査員の回答が拒否権的な効力を持つことを認めているが、数学的な設定を僅かに変えることで全審査員の回答の多数決という形式を持つより不公平感の少ないメカニズムに変更できること、(3)提案されているメカニズムの自然さ、単純さについて直観的に訴えるのではなく公理的に特徴づけを行うことができれば、より望ましい研究となること、などの有益なコメントが得られた。特に(2)の設定の変更については追加的な研究を通じて、不公平感の縮小という心理的なメリットに留まらず、ゲームに関する共通知識について弱い仮定を課した場合でも望ましいランキングが選ばれるという意味で、均衡の頑健性を向上させるという理論的なメリットがあることも明らかになった。実験による検証についても、上記の設定の変更に伴うメカニズムの見直しに伴い最終的に中断に至ったものの、実験経済学者の竹内あい氏(現・立命館大学)のアドバイスを得つつ、実験目的の明確化、実験で用いるモデルの決定、メカニズム見直しによる影響も含めた予想される結果についての解釈、といった基本的な実験デザインを完了し、翌年以降の研究に向けた資源とすることができた。

 

Syllabus

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