KÅsaku Yosida
Kosaku Yosida (Japanese吉田 耕作, Yoshida Kosaku, born February 7, 1909 in Hiroshima, Japan, † 20 June 1990) was a Japanese mathematician who is known for his work in functional analysis.
Yosida studied at the University of Tokyo and was then at the Universities of Osaka and Nagoya, before in 1955 he became a professor at the University of Tokyo. 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 Gakushuin University.
Yosida was president of the Japanese Mathematical Society, 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 Japan Academy of Sciences.
One of his most important works he made in the theory of strongly continuous semigroups with the set of Hille - Yosida: Yosida could show in 1948 with the help of the so-called Yosida approximation to characterize the contractive strongly continuous semigroups. This was later expanded to general strongly continuous semigroups. His textbook of functional analysis in 1965 found widespread use.
In 1954 he gave a plenary lecture at the International Congress of Mathematicians in Amsterdam (Semi Group theory and the integration of problem- diffusion equations ).
Writings
- Kosaku Yosida: Functional Analysis. Classics in Mathematics. 6th edition. Springer -Verlag, Berlin 1995, ISBN 3-540-58654-7.
- Kosaku Yosida: Collected papers. Springer -Verlag, Tokyo, 1992, ISBN 4-431-70111-7.
- Kosaku Yosida: Lectures on differential and integral equations. Dover Publications, Inc., New York, 1991, ISBN 0-486-66679-4.