Yasutaka Ihara

Yasutaka Ihara, born on May 3, 1938 in Tokyo Prefecture, is a Japanese mathematician and professor emeritus at the Research Institute for Mathematical Sciences, whose work in number theory includes Ihara's lemma and the Ihara zeta function. He received his PhD at the University of Tokyo in 1967, worked at the Institute for Advanced Study from 1965 to 1966, and was a professor at the University of Tokyo and then at the Research Institute for Mathematical Sciences of Kyoto University, retiring in 2002 and then becoming a professor at Chuo University. He has worked on geometric and number theoretic applications of Galois theory and introduced the Ihara zeta function in the 1960s. His doctoral students include Kazuya Kato.