Yasutaka Ihara

Yasutaka Ihara (Japanese伊 原 康隆, Yasutaka Ihara; * 1938 in the prefecture of Tokyo) is a Japanese mathematician who mainly deals with number theory.

Ihara received his doctorate in 1967 at the University of Tokyo. 1965/66 he was at the Institute for Advanced Study. He was a professor at Tokyo University and later at the Research Institute for Mathematical Science ( RIMS) of Kyoto University. In 2002, he retired. After that, he was a professor at Chuo University.

Ihara dealt among other things with geometric and number theoretic applications of Galois theory. From him the Ihara zeta function, which he introduced in the 1960s came. It allows for an interpretation in graph theory, such as Jean-Pierre Serre conjectured and Toshikazu Sunada showed 1985. It can be used also an analogue of the Riemann Hypothesis in graph theory formulated ( Sunada ).

In 1990 he gave a plenary lecture at the ICM in Kyoto ( Braids, Galois groups and some arithmetic functions) and in 1970 he was invited speaker at the ICM in Nice (Non abelian class fields over function fields in special cases ).

His doctoral Kazuya Katō heard.

Writings

  • On Congruence monodromy problem, Mathematical Society of Japan Memoirs, World Scientific 2009 (originally from lectures 1968/1969 )
  • With Michael Fried (Editor): Arithmetic fundamental groups and Noncommutative Algebra, American Mathematical Society, Proc. Symposium Pure Math Bd.70, 2002
  • As editor: Galois representations and arithmetic algebraic geometry, North Holland 1987
  • Kenneth Ribet, Jean- Pierre Serre (Editor): Galois Groups over Q, Springer, 1989 ( Proceedings of a Workshop, 1987)
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