Title： Monotone Perfection
Speaker： Yeneng Sun （National University of Singapore）
Time：4.15（Wednesday），14:00-16:00
Venue：2H Building 425, Science Park
Abstract：Monotone equilibrium in Bayesian games – often derived under single crossing and quasi-supermodularity – is a cornerstone of modern game theory. We show, however, that these conditions may not yield a behaviorally meaningful prediction: we construct an ordered Bayesian game that satisfies them yet admits no monotone equilibrium in admissible strategies. To address this critical issue, we introduce perfect monotone equilibrium, which incorporates small unintended moves to ensure robustness to small mistakes and admissibility. We establish existence under the stronger assumptions of increasing differences and supermodularity, illustrate the results in multi-unit auctions, and extend the analysis to Bertrand competition as well as first-price and all-pay auctions.
About the Speaker：孙业能现任新加坡国立大学文理学院共同院长、理学院院长与讲席教授，并兼任数学与经济学教授。其研究聚焦数理经济学、博弈论与概率论；他建立静态与动态的精确大数定律，为现代宏观经济学以及劳动、金融经济学中的多类核心模型奠定了严谨的数学基础。他曾获新加坡国家科学奖与新国大杰出研究奖，现为经济理论促进学会会士、新加坡国家科学院院士，并于第七届世界博弈论大会作平行主旨演讲；曾任新国大经济系系主任与风险管理研究所所长，并于2023年获新加坡共和国总统颁授公共行政（银）奖章。
