アブストラクト：
独立な高次元確率ベクトルの和の成分の最大値として与えられる統計量の分布の近似は、高次元パラメータに対する仮説検定や一様信頼区間の構成を行う上で重要な役割を果たす。V. Chernozhukov, D. ChetverikovおよびK. Katoらによる近年の研究によって、そのような最大値統計量の分布に対する正規型の近似やブートストラップ近似は、次元がサンプル数よりもはるかに大きいような超高次元の設定においても適当なモーメント条件下で正当化できることが明らかにされた。一方で、データの歪度がある程度大きい場合、スチューデント化を行わない場合であっても、高次元の設定では3次モーメントまでマッチさせるようなブートストラップ近似の方が正規型の近似よりも有限標本でのパフォーマンスが優れていることが数値実験によって観察されているが、既存の理論的結果はこのことを説明できない。本報告では、漸近展開を用いることでこの現象が理論的に説明できることを示す。特に、母集団の共分散行列が一定の条件を満たす場合、次元がサンプル数よりも大きい状況では3次モーメントまでマッチさせるようなブートストラップ近似がスチューデント化せずとも2次の精度を持つというblessing of dimensionality phenomenonが現れる。

【Paper】

Abstract: The technical change from steam engines to electric motors dramatically transformed manufacturing activities during the Second Industrial Revolution. This paper explores how this technical change progressed and what consequences it brought for the evolution of economic geography. I hypothesize that electric motors powered by purchased electricity lowered barriers to entry in the manufacturing sector due to their significantly lower fixed costs compared to steam engines. To examine this hypothesis, I exploit the historical expansion of electricity grids in early 20th-century Japan and newly digitized establishment-level official records, including information on power sources of establishments. Descriptive evidence shows that electric motors were widely adopted by establishments of all sizes, whereas steam engines were primarily adopted by large establishments, indicating lower fixed costs of electric motors. Using hydropower potential as an instrument, I document that new entrants played a crucial role in driving this technical change and stimulating manufacturing activities. Overall, these findings lend substantial support for the hypothesis. Furthermore, I find that regions with earlier electricity access experienced substantial population growth throughout the early 20th century and exhibit larger economic activity even in the 21st century. These findings suggest a persistent impact of this technological shock: the rapid increase in entrant activities generated agglomeration forces in manufacturing, with accumulated effects still visible in the spatial distribution of economic activity today.

“Strategy-proof rules in object allocation problems with hard budget constraints and income effects”
Yuya Wakabayashi (Kyoto university)
“Sequential dictatorship rules in multi-unit object assignment problems with money”
Masahiro Kawasaki (Kyoto university)
“Dynamic Many-to-One Matching under Constraints”
Rui He (Kyoto university)

Abstract: https://github.com/QuantEcon/kyoto_2025

Abstract: The exclusion restriction plays a key role in the identification of LATE (Imbens & Angrist (1994), Angrist, Imbens & Rubin (1996)). We discuss a particularly ubiquitous way in which the exclusion restriction would seem to be generically violated. We argue that this form of violation is not addressed in the many applications that rely on this influential framework. We characterize the bias that this particular violation gives rise to and, more constructively, discuss how to use the particular structure of the violation along with milder assumptions and additional data to restore identification. We provide sharper bounds by exploiting the specific structure of the exclusion restriction violation we uncover. Further, with an additional assumption which is plausible in many empirical settings, we restore point identification of LATE. We illustrate with examples and discuss why this violation is likely present in most existing empirical applications. We discuss how our arguments naturally extend to other IV settings where the LATE parameter is commonly invoked, such as randomized controlled trials with imperfect compliance and fuzzy regression discontinuity designs. Moving beyond LATE, we also consider how the same problems and solution ideas apply to identification of the MTE profile and more structural “Roy” models of treatment effects.