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English/日本語

Welcome to the webpage of Kenichi Bannai. I am currently a Professor at the Department of Mathematics, Faculty of Science and Technology, at Keio University. My main topic of research is Arithmetic Geometry, with a focus on conjectures concerning the special values of Hasse-Weil $L$-functions, e.g. the Beilinson-Bloch-Kato Conjectures. Since my thesis, I have mostly been studying the polylogarithm, a certain class in absolute cohomology of motivic origin which we hope will be useful in understanding the conjectures. Find here the video and slides of my talk at the Séminaire de Géométrie Arithmétique Paris-Pékin-Tokyo concerning my research. I am currently the Principal Investigator of the KAKENHI Grant-in-Aid for Scientific Research (S) project 18H05233 "Strategic research to construct motivic units using new symmetry", FY2018-2022.

I am also the Team Leader of the Mathematical Science Team at RIKEN AIP, a research center within RIKEN for Artificial Intelligence especially Machine Learning. Our team consists of graduate students and postdoctoral researchers with backgrounds in pure mathematics and theoretical physics. See the presentation at the 18th AIP Open Seminar to understand the activities of the Mathematical Science Team. Furthermore, I am currently a co-investigator of the JST CREST project JPMJCR1913 "Creation of a complex dynamics computational platform based on operator-theoretic data analysis", FY2019-2024, headed by Yoshinobu Kawahara of Kyushu University.

Together with Makiko Sasada of the University of Tokyo, I am a founding member of Suri-Joshi（数理女子）, a network of volunteers to encourage and help girls and women to pursue a career in Mathematics. I strongly believe that society, including the Mathematical community, should be open, friendly, and fair to all people regardless of their gender, socio-economic status, race, nationality, etc. Find here the report Gender in Mathematics in Japan [PDF].

### Research Activities

• I obtained my Ph.D. in 2000 from the Graduate School of Mathematics, University of Tokyo. My advisor was Takeshi Saito. I was a faculty member of the Graduate School of Mathematics, Nagoya University, from September 2001 to March 2008. I was a visiting researcher at ENS Paris from April 2005 to March 2007, as a JSPS postdoctral research fellow. My host was Yves André.
• I have been a member of the Department of Mathematics, Faculty of Science and Technology of Keio University since April 2008. I was the Principal Investigator of the KAKENHI Grant-in-Aid for Young Scientists (S) project 21674001 "Strategic Research to solve certain conjectures in Arithmetic Geometry", FY2009-2013.
• I was the Principal Investigator of the Keio Institute of Pure and Applied Sciences (KiPAS) program, FY2014-2018. During this period, I was also the Principal Investigator of the KAKENHI Grant-in-Aid for Grant-in-Aid for Scientific Research (A) project 26247004 "Strategic Research to solve certain conjectures in Arithmetic Geometry with a focus on Eisenstein classes", FY2014-2018. I was also a co-investigator of the JSPS Core-to-Core program "Foundation of a Global Research Cooperative Center in Mathematics focused on Number Theory and Geometry" FY2014-2018, headed by Masato Kurihara of Keio University.
• Since October 2016, I am the Team Leader (Principle Investigator) of the Mathematical Science Team of the Generic Technology Research Group of RIKEN AIP. The team consists of graduate students and postdoctoral researchers with background in pure mathematics and theoretical physics. Our primary objective is to apply mathematics to contribute to the field of machine learning. See the presentation at the 18th AIP Open Seminar to understand the activities of the Mathematical Science Team.
• I was a local organizer of the Iwasawa 2017 conference commemorating the 100th anniversary of Kenkichi Iwasawa's birth. I am also an editor of the proceedings: Development of Iwasawa Theory — the Centennial of K. Iwasawa’s Birth.
• I am currently the Principal Investigator of the KAKENHI Grant-in-Aid for Scientific Research (S) project 18H05233 "Strategic research to construct motivic units using new symmetry", FY2018-2022. I am also currently a co-investigator of the JST CREST project JPMJCR1913 "Creation of a complex dynamics computational platform based on operator-theoretic data analysis", FY2019-2024, headed by Yoshinobu Kawahara of Kyushu University.
• I am an organizer of the conference Arithmetic Geometry – Takeshi 60, held in honor of the 60th birthday of Takeshi Saito, to be held September 6 –10, 2021 at the Graduate School of Mathematical Sciences, The University of Tokyo. I am also an organizer of Development of Iwasawa theory, A conference in honor of the 60th birthday of Masato Kurihara, to be held in 2022, at the Department of Mathematics, Faculty of Science and Technology, Keio University.
• Together with Makiko Sasada of the University of Tokyo, I am a founding member of Suri-Joshi, a network of volunteers to encourage and help girls and women to pursue a career in Mathematics. I strongly believe that society, including the Mathematical community, should be open, friendly, and fair to all people regardless of their gender, socio-economic status, race, nationality, etc.