Kentaro Tomoeda joined the Economics Discipline Group of UTS Business School in July 2016. He received his PhD in economics from Harvard University in 2016.
Can supervise: YES
Microeconomic Theory, Mechanism Design, Market Design, Economics of Education
安田洋祐 2010, 学校選択制のデザイン ゲーム理論アプローチ, NTT出版.
© 2019 Elsevier Inc. This paper identifies a condition for an efficient social choice rule to be fully implementable when we take into account investment efficiency. To do so, we extend the standard implementation problem to include endogenous ex ante and ex post investments. In our problem, the social planner aims to achieve efficiency in every equilibrium of a dynamic game in which agents strategically make investments before and after playing the mechanism. Our main theorem shows that a novel condition commitment-proofness is sufficient and necessary for an efficient social choice rule to be implementable in subgame-perfect equilibria. The availability of ex post investments is crucial in our model: there is no social choice rule that is efficient and implementable in subgame-perfect equilibria without ex post investments. We also show that our positive result continues to hold in the incomplete information setting.
This note shows that the first-price auction fully implements efficient investments when agents make not only ex ante but also ex post investments. The essential assumptions of our model are that (i) each agent can invest before and after participating in the auction under the same cost function and (ii) the cost functions are common knowledge among agents. In any equilibrium of our model, the most efficient agent always wins and makes the efficient level of investment.