Mitio (Michio) Nagumo ( ja, 南雲道夫; May 7, 1905 – February 6, 1995) was a Japanese mathematician, who specialized in the theory of differential equations. He gave the first necessary and sufficient condition for positive invariance of

closed set In geometry, topology, and related branches of mathematics, a closed set is a set whose complement is an open set. In a topological space, a closed set can be defined as a set which contains all its limit points. In a complete metric space, a cl ...

s under the flow induced by ordinary differential equations ( Nagumo/Bony-Brezis theorem).

Biography

Mitio Nagumo graduated from the Department of Mathematics at the

Imperial University of Tokyo , abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project by ...

in March 1928. In March 1931 he was appointed Lecturer in the Faculty of Technology at the Imperial University of Kyushu. In February 1932 he left

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

for an academic visit to Göttingen, where he remained for two years. Upon his return from Göttingen in March 1934, he was appointed Lecturer in the Department of Mathematics at the Imperial University of Osaka, and was promoted to Associate Professor in September that year, becoming Professor in the Faculty of Science in March 1936. In March 1937 Nagumo received a Doctor of Science degree from the

. In the 1960s he made a number of academic visits abroad, spending time at the Courant Institute of Mathematical Sciences (where he visited

Kurt Friedrichs Kurt Otto Friedrichs (September 28, 1901 – December 31, 1982) was a noted German-American mathematician. He was the co-founder of the Courant Institute at New York University, and a recipient of the National Medal of Science. Biography Friedri ...

and other old acquaintances from his time at Göttingen) and the

Federal University of Rio Grande do Sul The Federal University of Rio Grande do Sul ( pt, Universidade Federal do Rio Grande do Sul, UFRGS) is a Brazilian public federal research university based in Porto Alegre, Rio Grande do Sul. UFRGS is among the largest and highest-rated univers ...

in 1960, followed by a visit to the National Tsing Hua University in 1963-64. He retired from

Osaka University , abbreviated as , is a public research university located in Osaka Prefecture, Japan. It is one of Japan's former Imperial Universities and a Designated National University listed as a "Top Type" university in the Top Global University Project. ...

in December 1966, after which he was granted the title of Honorary Professor. He was subsequently appointed Professor at Sophia University, from which he retired in March 1976, having reached mandatory retirement age. Much of Nagumo's original work was published in Japanese and

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

, however his research and teaching have influenced numerous mathematicians (especially in

) who have since made many of his results available in English.

Works

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Literature

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References

{{DEFAULTSORT:Nagumo, Mitio 1905 births 1995 deaths 20th-century Japanese mathematicians University of Tokyo alumni Academic staff of Kyushu University Academic staff of Osaka University Academic staff of Sophia University