News
The conference "L-functions and Motives in Niseko 2024" will be held on 15-20, September 2024.
Research Interests
Number Theory and Arithmetic Geometry
Keywords : Special values of L-functions, Cyclotomic Fields, Complex Multiplication, Periods, Regulators, Algebraic Cycles, Motivic Cohomology, Hypergeometric Functions.
Publications and Preprints
On the adelic Gaussian hypergeometric function (with M. Asakura), arXiv:2408.08012.
Motivic Gauss and Jacobi sums (with T. Yamazaki), arXiv:2402.06072.
Hypergeometric functions over finite fields, Ramanujan J., 63 (2024), 55-104, arXiv:2108.06754.
Product formulas for hypergeometric functions over finite fields (with T. Senoue), Res. Number Theory 8 (2022): 80.
A new approach to hypergeometric transformation formulas, Ramanujan J., 55 (2021), 793-816.
Regulators of K1 of hypergeometric fibrations (with M. Asakura), Arithmetic L-functions and geometric differential methods, Progress in Math. 338 (2021), 1-30.
A functional logarithmic formula for hypergeometric functions 3F2 (with M. Asakura), Nagoya Math. J., 236 (2019), 29-46.
An algebro-geometric study of the special values of hypergeometric functions 3F2 (with M. Asakura and T. Terasoma), Nagoya Math. J., 236 (2019), 47-62.
CM periods, CM regulators and hypergeometric functions, II (with M. Asakura), Math. Z. 289 (2018), 1325-1355.
CM periods, CM regulators and hypergeometric functions, I (with M. Asakura), Canad. J. Math. 70 (2018), 481-514.
Homology of the Fermat tower and universal measures for Jacobi sums, Canad. Math. Bull. 59 (2016), 624-640.
On special values of Jacobi-sum Hecke L-functions, Experim. Math. 24 (2015), 247-259.
On the Abel-Jacobi maps of Fermat Jacobians, Math. Z. 270 (2012), 423-444.
Certain values of Hecke L-functions and generalized hypergeometric functions, J. Number Theory 131 (2011), 648-660.
On the regulator of Fermat motives and generalized hypergeometric functions, J. reine angew. Math. 660 (2011), 27-82.
Recent progress on the finiteness of torsion algebraic cycles, Class Field theory - Its Centenary and Prospect (K. Miyake, ed.), Adv. Stud. Pure Math., 30, 313-323, Math. Soc. Japan, Tokyo, 2001.
Selmer groups and zero-cycles on the Fermat quartic surface, J. reine angew. Math. 525 (2000), 113-146.
Note on conjectures of Beilinson-Bloch-Kato for cycle classes, Manuscripta Math. 101 (2000), 115-124.
Fourth-order Fermat surfaces and Selmer groups (in Japanese), Algebraic number theory and related topics (Kyoto, 1997), Sūrikaisekikenkyūsho Kōkyūroku 1026 (1998), 224-231.
Texts in Japanese 日本語の文章
著書
「数論におけるコホモロジー」, 安藤哲哉編「コホモロジー」所収, 日本評論社, 2002.
書評
吉永正彦「周期と実数の0-認識問題 - Kontsevich-Zagierの予想」, 数学 72 (3), 2020, 日本数学会.
一般向けの講義ノート
超幾何関数と数論 (2018, 千葉県立船橋高等学校)
対称群と婚姻規則 (2017, 千葉大学)
ガウスの整数と直角三角形 (2015, 千葉県立船橋高等学校)
有限体と方程式の解の数 (2010, 日本数学オリンピック夏季セミナー)
翻訳（私家版）
ヴェイユ「クンマー全集・序文」(1975)（準備中）
その他
研究室紹介（ポスター, 2018）
Contact Information
Mailing Address: Department of Mathematics and Informatics, Chiba University, Yayoicho 1-33, Inage, Chiba, 263-8522 Japan
Office: Room 312, Faculty of Science Building 1 (no.5 in the campus map)
Email: otsubo@math.s.chiba-u.ac.jp