Kosaku Yosida, born on February 7, 1909, was brought up in Tokyo. Having
majored in Mathematics at University of Tokyo, he was appointed to
Assistant at Osaka University in 1933 and promoted to Associate
Professor in 1934. He re- ceived the title of Doctor of Science from
Osaka University in 1939. In 1942 he was appointed to Professor at
Nagoya University, where he worked very hard with his colleagues to
promote and expand the newly established Department of Mathe- matics. He
was appointed to Professor at Osaka University in 1953 and then to
Professor at University of Tokyo in 1955. After retiring from University
of Tokyo in 1969, he was appointed to Professor at Kyoto University,
where he also acted as Director of the Research Institute for
Mathematical Sciences. He retired from Kyoto University in 1972 and
worked as Professor at Gakushuin University until 1979. Yosida acted as
President of the Mathematical Society of Japan, as Member of the Science
Council of Japan, and as Member of the Executive Committee of the
International Mathematical Union. In 1967 he received the Japan Academy
Prize and the Imperial Prize for his famous work on the theory of
semigroups and its applications. In 1971 he was elected Member of the
Japan Academy. Yosida went abroad many times to give series of lectures
at mathematical in- stitutions and to deliver invited lectures at
international mathematical symposia.
