Analysis on Repeated Games with Automatic and Optional Monitoring

• Project/Area Number: 17K03625
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Economic theory
• Research Institution: Kobe University
• Principal Investigator: Miyahara Yasuyuki 神戸大学, 経営学研究科, 教授 (80335413)
• Co-Investigator(Kenkyū-buntansha): 関口 格 京都大学, 経済研究所, 教授 (20314461)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 有限回繰り返しゲーム / 私的観測 / 自動観測 / オプション観測 / フォーク定理 / ゲーム理論 / 繰り返しゲーム / 観測構造 / 観測オプション / 経済理論

Outline of Final Research Achievements

This study is concerned with repeated games with automatic and optional monitoring. The main objective of this study is to identify how the equilibrium payoff set changes as this probability increases, assuming a situation in which we automatically know complete information about the actions chosen by the other players with a certain probability The main objective of this study is to identify how the equilibrium gain set changes when this probability increases. For any stage game and any number of repetition, we found that the equilibrium payoff set gets large when the automatic observation probability is small, given two types of automatic observation probabilities. We also show that the Folk Theorem holds when the Nash equilibrium of the stage game is unique.

Academic Significance and Societal Importance of the Research Achievements

本研究の主要命題は、情報が自動的に伝達される確率が小さい方がある意味、社会にとって好ましいということをこの命題は主張している。一見すると現実の感覚からは逆説的に思われるが、実を言うとゲーム理論的には納得のいく主張になっている。それは自動的に情報が得られなかった場合には観測するオプションがあるため、戦略的自由度が高いことによる。ただし、戦略的自由度が高いことが直ちに均衡利得集合を拡大するということはそれほど自明ではない。この直感が実際に正しいことを明らかにしたことが本研究の大きな貢献である。また、段階ゲームのナッシュ均衡が一意であったとしても、フォーク定理が成り立つことを示したことも貢献である。

Research Products

• [Journal Article] 会議による社会的損失に関する一考察 (2018)
  • Author(s): 宮原泰之
  • Journal Title: 国民経済雑誌 Volume: 217 Pages: 61-77
  • NAID: 120006624209
• [Presentation] A Folk Theorem for Infinitely Repeated Games with Equivalent Payoffs under Optional Monitoring (2021)
  • Author(s): Tadashi Sekiguchi
  • Organizer: 91st Annual Meeting of the Southern Economic Association
  • Int'l Joint Research
• [Presentation] A Folk Theorem for Infinitely Repeated Games with Equivalent Payoffs under Optional Monitoring (2020)
  • Author(s): 関口 格
  • Organizer: ゲーム理論ワークショップ2020
• [Presentation] A Folk Theorem for Repeated Games with Equivalent Payoffs under Optional Monitoring (2019)
  • Author(s): Tadashi Sekiguchi
  • Organizer: The Lisbon Meetings in Game Theory and Applications
  • Int'l Joint Research
• [Presentation] Finitely Repeated Games with Automatic and Optional Monitoring (2019)
  • Author(s): 関口格
  • Organizer: Theory Workshop at Department of Economics, University of Rochester
  • Int'l Joint Research / Invited
• [Presentation] Communication Enhancement through Information Acquisition by Uninformed Player (2019)
  • Author(s): 宮原泰之
  • Organizer: WEAI Conference
  • Int'l Joint Research
• [Presentation] Finitely Repeated Games with Automatic and Optional Monitoring (2017)
  • Author(s): 関口格
  • Organizer: 2017 Asian Meeting of the Econometric Society
• [Presentation] Communication Enhancement through Information Acquisition by Uninformed Player (2017)
  • Author(s): 宮原泰之
  • Organizer: International Conference on Game Theory
• [Presentation] Finitely Repeated Games with Automatic and Optional Monitoring (2017)
  • Author(s): 関口各
  • Organizer: 日本経済学会
• [Book] 組織の経済学 (2019)
  • Author(s): 伊藤 秀史、小林 創、宮原 泰之
  • Total Pages: 414
  • Publisher: 有斐閣
  • ISBN: 9784641165502