Kosaku Yosida

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Kōsaku Yosida (1969)

Kōsaku Yosida ( Jap . 吉田耕作 , Yoshida Kosaku * 7. February 1909 in Hiroshima Prefecture , Japan ; † 20th June 1990 ) was a Japanese mathematician who through his work in the functional analysis has become known.

Life

Yosida studied at the University of Tokyo and then was at the Universities of Osaka and Nagoya before becoming a professor at the University of Tokyo in 1955. From 1969 he was a professor at Kyoto University and director of the Research Institute for Mathematical Sciences . From 1972 to 1979 he was a professor at Gakushūin University .

Yosida was President of the Japanese Mathematical Society , a member of the Science Council of Japan and a member of the Executive Committee of the International Mathematical Union . In 1971 he became a member of the Japanese Academy of Sciences and in 1977 a member of the American Academy of Arts and Sciences . In 1982 he was accepted as a foreign member of the Academy of Sciences of the USSR .

He performed one of his most important works in the theory of the strongly continuous semigroups with Hille-Yosida's theorem : Yosida was able to show a characterization of the contractive strongly continuous semigroups in 1948 with the help of the so-called Yosida approximation. This could later be extended to general, strongly continuous semi-groups. His textbook on functional analysis from 1965 was widely used.

In 1933 he gave a new proof of Malmquist's theorem for the characterization of the Riccatian differential equation in the complex with the help of Nevanlinna's value distribution theory and generalized the theorem.

In 1954 he gave a plenary lecture at the International Congress of Mathematicians in Amsterdam ( Semigroup theory and the integration problem of diffusion equations ).

Fonts

  • Kōsaku Yosida: Functional Analysis . Classics in Mathematics . 6th edition. Springer-Verlag, Berlin 1995, ISBN 3-540-58654-7 .
  • Kōsaku Yosida: Collected papers . Springer-Verlag, Tokyo 1992, ISBN 4-431-70111-7 .
  • Kōsaku Yosida: Lectures on differential and integral equations . Dover Publications, Inc., New York 1991, ISBN 0-486-66679-4 .

Web links

swell

  • Preface of the Collected Papers , Springer-Verlag, Tokyo 1992 (contains a short curriculum vitae)

Individual evidence

  1. Foreign members of the Russian Academy of Sciences since 1724. Kōsaku Yosida. Russian Academy of Sciences, accessed September 2, 2015 .
  2. K. Yosida, A generalization of Malmquist's theorem, Japan J. Math., Vol. 9, 1932, pp. 253-256