email: please see my working paper
Backgrounds
2023-present, Professor, Kanagawa University
2023-present, Specially Appointed Professor, Hitotsubashi University
2012-2023, Professor, Hitotsubashi University
2005-2012, Professor, Yokohama National University
2002-2005, Associate Professor, Yokohama National University
1999-2002, Assistant Professor, University of Tsukuba
1988-1999, Economist, Bank of Japan
Ph.D. 1997, Economics, Stanford University
M.S. 1988, Engineering, The University of Tokyo
B.S. 1986, Engineering, The University of Tokyo
Research
Refereed publications
A Shapley Value Representation of Potential Games, Games and Economic Behavior 31 (2000), 121-135.
Robust Equilibria of Potential Games, Econometrica 69 (2001), 1373-1380.
Best Response Equivalence (with Stephen Morris), Games and Economic Behavior 49 (2004), 260-287.
Generalized Potentials and Robust Sets of Equilibria (with Stephen Morris), Journal of Economic Theory 124 (2005), 45-78.
Incomplete Information Games with Multiple Priors (with Atsushi Kajii), Japanese Economic Review 56 (2005), 332-351.
Equivalence of the Dempster-Shafer Rule and the Maximum Likelihood Rule Implies Convexity (with Atsushi Kajii), Economics Bulletin 4-10 (2005), 1-6.
Agreeable Bets with Multiple Priors (with Atsushi Kajii), Journal of Economic Theory 128 (2006), 299-305.
Correlated Quantal Responses and Equilibrium Selection, Games and Economic Behavior 57 (2006), 361-369.
A Note on Discrete Convexity and Local Optimality, Japan Journal of Industrial and Applied Mathematics 23 (2006), 21-29.
Cominimum Additive Operators (with Atsushi Kajii and Hiroyuki Kojima), Journal of Mathematical Economics 43 (2007), 218-230.
Discrete Concavity for Potential Games, International Game Theory Review 10 (2008), 137-143.
Correlated Equilibrium and Concave Games, International Journal of Game Theory 37 (2008), 1-13.
Interim Efficient Allocations under Uncertainty (with Atsushi Kajii), Journal of Economic Theory 144 (2009), 337-353.
Coextrema Additive Operators (with Atsushi Kajii and Hiroyuki Kojima), in: S. K. Neogy, A. K. Das and R. B. Bapat, Editors, Modeling, Computation and Optimization, World Scientific (2009), pp. 73-95.
Bayesian Potentials and Information Structures: Team Decision Problems Revisited, International Journal of Economic Theory 5 (2009), 271-291. This article is available online at Blackwell Synergy (www.blackwell-synergy.com).
The Ambiguity Premium vs. the Risk Premium under Limited Market Participation, Review of Finance 15 (2011), 245-275.
The Myerson Value for Complete Coalition Structures (with Atsushi Kajii and Hiroyuki Kojima), Mathematical Methods of Operations Research 74 (2011), 427-443.
Effects of Symmetry on Globalizing Separated Monopolies to a Nash-Cournot Oligopoly (with Hisao Kameda), International Game Theory Review 14 (2012), DOI: 10.1142/S0219198912500090.
Radner's Theorem on Teams and Games with a Continuum of Players (with Yasunori Yoshizawa), Economics Bulletin 33-1 (2013), 72-77.
The Social Value of Public Information with Convex Costs of Information Acquisition, Economics Letters 125 (2014), 249-252.
Characterizing Social Value of Information (with Yasunori Yoshizawa), Journal of Economic Theory 158 (2015), 507-535. Online appendix
Bayesian Nash Equilibrium and Variational Inequalities, Journal of Mathematical Economics 63 (2016), 139-146.
The Lucas Imperfect Information Model with Imperfect Common Knowledge, Japanese Economic Review 71 (2020), 85-100.
Imprecise Information and Second-Order Beliefs, Communications in Economics and Mathematical Sciences 1 (2022), 67-86.
Working papers
On the Pettis Integral Approach to Large Population Games (with Masaki Miyashita), March 2024.
LQG Information Design (with Masaki Miyashita), revised December 2023.
Impacts of Public Information on Flexible Information Acquisition, April 2022.
Optimal and Robust Disclosure of Public Information, March 2022.
Robust Voting under Uncertainty (with Satoshi Nakada and Shmuel Nitzan), revised December 2021.
Strategic Ambiguity in Global Games, revised February 2023.
Belief-free Preference Aggregation (with Satoshi Nakada, Shmuel Nitzan, and Norio Takeoka), August 2020.
Incomplete Information Robustness (with Stephen Morris), March 2020.
Self-Control Games (with Norio Takeoka), revised March 2016. Online appendix
Global Games and Ambiguous Information: An Experimental Study (with Toshiji Kawagoe), revised October 2015.
Welfare Effects of Information Acquisition Costs, October 2013.
Non-Atomic Potential Games and the Value of Vector Measure Games, revised June 2008.
Quantal Response Equilibria and Stochastic Best Response Dynamics, revised June 2002.
Asymmetric Effects of Monetary Policy: Japanese Experiences in the 1990s (with Ryo Kato and Tsutomu Watanabe), 1999.
Economic Welfare and Competition in Oligopolistic Markets, 1991.
Papers in conference proceedings
Contagious Expectation and Malfunctions of Markets: Some Lessons from Japanese Financial Institution Failures of 1997 (with Tokiko Shimizu), Proceedings of the Second Joint Central Bank Research Conference on Risk Measurement and Systemic Risk, pp. 507-525, 1998.
Transparency and Liquidity in Securities Markets, Market Liquidity: Research Findings and Selected Policy Implications, Committee on the Global Financial System, Bank for International Settlements, 1999.
Dempster-Shafer Updating and Additivity of the Core (with Atsushi Kajii), RIMS Kokyuroku 1371 (2004), 110-115.
Links
Prof. Shun-ichi Amari: his textbook on information geometry, his lecture on information geometry
Department of Mathematical Engineering and Information Physics, The University of Tokyo
Miscellaneous
A.B. Migdal: On the Psychology of Scientific Creativity, Contemporary Physics 20 (1979), 121-148.
Summary in Japanese
"The driving force behind scientific creativity should not be the desire to bring about a scientific revolution; nor should all one's efforts be directed towards achieving success, but one should be motivated by a love of knowledge, a capacity to wonder at and delight in each small success and, above all, a feeling for the beauty of science. It is important to develop impeccable conscientiousness and to learn to reduce the most complex questions to extreme simplicity and clarity; to find a way out of many psychological contradictions; to be guided by intuition but not to put one's trust in it; to be conscious of all the difficulties, but to be able temporarily to divert one's attention from them; to believe in a result but at the same time to search patiently for a way to refute it; to find one's own style of working but to be able to change it with experience and with each new major discovery: in brief one must aim to understand everything."
さて，研究者の最高の栄誉は『島を発見した人』になって後世にその名を留めることであるとされている．研究者なら誰しもこの栄誉に恵まれたいと願っている．しかし，そのためには，本当に『何も発見できない』だけでなくシケの海であえなく『溺れ死ぬ』かもしれないという大きなリスクを覚悟しておかなければならない．このリスクは一般に “all or nothing”リスクと呼ばれているものであり，身も心もボロボロに擦り切れて社会的落伍者となる危険である（このことは，人類の長い歴史の中ですでに実証ずみである）．だが，翻って考えてみると，この世は研究とは限らずあらゆる種類の危険に満ち満ちている．安全で確実な人生など１つもないのである．ましてや，安全だけにしがみついた人生など空疎そのものでしかない．であるとするならば，そして，いったん研究者としての道を踏み出してしまったのであるとするならば，いかなることがあっても『島を発見する人』たらんとする研究者魂だけは決して捨てまい．それでベストを尽くしたあとは思い煩うことは何もない，ただ天命に任せればよいではないか．このような信条こそが『極道』すなわち『道を極める』ことに人生を掛けた者達の心意気というものであろう（極道から心意気をとったら何も残らない！）．いたずらに右顧左ベンせず，腹を据え捨て身で掛って行くうちには，極道にもそれなりの人格が備わって来るに違いないのである．美しいものに対する感受性とかけがえのない個性だけが頼りの極道達に幸いあれと祈らざるを得ない由縁である．