June 8, 2026
The University of Tokyo Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI)
Toshiyuki Kobayashi, The University of Tokyo Graduate School of Mathematical Sciences Professor and Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI) Senior Fellow, has been named a recipient of the 67th Fujihara Award, the Fujihara Foundation of Science announced.
The award was established in 1960 and awards two prizes each year to researchers who have made distinguished contributions to the advancement of science and technology in the field of fundamental and applied natural sciences.
Kobayashi is being recognized for his contributions to “Mathematical Analysis of Infinite-Dimensional Symmetries.”
For more than 35 years, he has led mathematical research on the international stage. His work on infinite-dimensional symmetries has formulated and identified previously unrecognized fundamental problems, integrating algebra, geometry, and analysis at a profound level.
Kobayashi’s work on the problem of restrictions and branching of infinite-dimensional representations—long considered difficult to understand systematically—discovered discretely decomposable restrictions, thereby making him the first to theorize their structure. Furthermore, he was the first to establish a comprehensive general theory of the action of discontinuous groups in geometry without a metric structure. He also introduced an original theory of “visible actions” on complex manifolds, establishing a unified framework for generating multiplicity-free representations in both finite- and infinite-dimensional settings.
Kobayashi also carried out pioneering work in introducing conformal geometry into minimal representations, leading to a new field known as “global analysis with minimal representations as a motif.” His work on the construction and classification theory of symmetry-breaking operators has played a central role in the development of new research fields over the past 15 years.
Kobayashi’s work has fostered deep connections between different fields of mathematics and has been highly regarded by his peers internationally as a fundamental contribution that has influenced a wide range of mathematical disciplines.
Related links
Professor Toshiyuki KOBAYASHI receives the 67th Fujihara Award (The University of Tokyo Graduate School of Mathematical Sciences)
Past Recipients of the Fujihara Award (The Fujihara Foundation of Science)
Professor Toshiyuki Kobayashi’s website
Comprehensive overview of Professor KOBAYASHI's work: Goldman et al., "The Mathematical Work of Toshiyuki Kobayashi" Progress in Mathematics, Birkhäuser-Springer, pp. 1-102, 2025.
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Principal Investigator Toshiyuki Kobayashi elected Fellow of the American Mathematical Society (November 1, 2016)
Toshiyuki Kobayashi Awarded the 2015 JMSJ Outstanding Paper Prize (April 3, 2015)
Prof. Toshiyuki Kobayashi is awarded the Medal with Purple Ribbon (April 28, 2014)
The 2010 Inoue Science Prize to Toshiyuki Kobayashi (16 December 2010)
