Toshiyuki Kobayashi

is a Japanese mathematician known for his original work in the field of Lie theory, and in particular for the theory of discontinuous groups (lattice in Lie groups) and the application of geometric analysis to representation theory. He was a major developer in particular of the theory of discontinuous groups for non-Riemannian homogeneous spaces and the theory of discrete breaking symmetry in unitary representation theory.

He has been a member of the Science Council of Japan since 2006, Board of Trustees of the Mathematical Society of Japan (2003–2007), the Editor in Chief of the Journal of the Mathematical Society of Japan (2002–2006), and currently is the Managing Editor of the Japanese Journal of Mathematics since 2006.

Academic career Ph.D./Doctor of Science, 1990, University of Tokyo Assistant Professor, 1987–1991, Associate Professor, 1991–2001, University of Tokyo Associate Professor, 2001–2003, RIMS, Kyoto University Full Professor, 2003–2007, RIMS, Kyoto University Full Professor, 2007-, University of Tokyo Principal Investigator, 2011-, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)

He has held many invited positions including Institute for Advanced Study in Princeton, USA (1991–1992), Mittag-Leffler Institute, Sweden (1995–1996), Université de Paris, Université de Paris VI, France (1999), Harvard University, USA (2000–2001, 2008), Université de Paris VII, France (2003), Max-Planck-Institut für Mathematik in Bonn, Germany (2007), IHES, France (2010; 2012; 2014; 2015; 2017; 2019; 2023; 2025), Jubilee Professorship, Chalmers University, Sweden (2013) and Yale University (2019)

Awards and honors

1997 - Takebe Prize, The Mathematical Society of Japan 1999 - Spring Prize, The Mathematical Society of Japan 2006 - Osaka Science Prize 2006/2007 - Sackler Distinguished Lecturer 2007 - JSPS Prize, The Japan Society for the Promotion of Science 2008 - The Humboldt Prize 2011 - Inoue Prize For Science 2014 - Medal with Purple Ribbon, Japan 2015 - JMSJ Outstanding Paper Prize 2017 class of Fellows of the American Mathematical Society "for contributions to the structure and representation theory of reductive Lie groups". 2022 - Doctorat Honoris Causa, University of Reims Champagne-Ardenne, France 2026 - Fujihara Award

Selected publications Journal articles

Books

Kobayashi, T. Discontinuous groups for non-Riemannian homogeneous spaces. In: B. Engquist and W. Schmid, editors, Mathematics Unlimited - 2001 and Beyond, pages 723-747. Springer-Verlag, 2001. .