was a

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

Early life

Iyanaga was born in

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

on April 2, 1906. He studied at the

University of Tokyo The University of Tokyo (, abbreviated as in Japanese and UTokyo in English) is a public research university in Bunkyō, Tokyo, Japan. Founded in 1877 as the nation's first modern university by the merger of several pre-westernisation era ins ...

from 1926 to 1929. He studied under

Teiji Takagi Teiji Takagi (高木貞治 ''Takagi Teiji'', April 21, 1875 – February 28, 1960) was a Japanese mathematician, best known for proving the Takagi existence theorem in class field theory. The Blancmange curve, the graph of a nowhere-differenti ...

. As an undergraduate, he published two papers in the ''Japanese Journal of Mathematics'' and the ''Proceedings of the Imperial Academy of Tokyo''. Both of his papers appeared in print in 1928. After completing his undergraduate degree in 1929, he stayed at Tokyo and worked under Takagi for his doctorate. He completed his Ph.D. in mathematics 1931.

Years in Europe

In 1931, Iyanaga obtained a scholarship from the

French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...

government. He also went to

Hamburg, Germany Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...

where he studied with

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

n mathematician

Emil Artin Emil Artin (; March 3, 1898 – December 20, 1962) was an Austrians, Austrian mathematician of Armenians, Armenian descent. Artin was one of the leading mathematicians of the twentieth century. He is best known for his work on algebraic number t ...

. In 1932, he attended the

International Congress of Mathematicians The International Congress of Mathematicians (ICM) is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union (IMU). The Fields Medals, the IMU Abacus Medal (known before ...

Zurich Zurich (; ) is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zurich. It is in north-central Switzerland, at the northwestern tip of Lake Zurich. , the municipality had 448,664 inhabitants. The ...

. During his time in Europe, he met with top mathematicians such as

Claude Chevalley Claude Chevalley (; 11 February 1909 – 28 June 1984) was a French mathematician who made important contributions to number theory, algebraic geometry, class field theory, finite group theory and the theory of algebraic groups. He was a found ...

Henri Cartan Henri Paul Cartan (; 8 July 1904 – 13 August 2008) was a French mathematician who made substantial contributions to algebraic topology. He was the son of the mathematician Élie Cartan, nephew of mathematician Anna Cartan, oldest brother of c ...

, and others.

Academic career

Iyanaga returned to Tokyo in 1934 and was appointed Assistant Professor at the

. From 1935 to 1939, he didn't publish any research papers. According to Iyanaga, it was because of the pressure of teaching and other business to which he was not accustomed. He managed to solve a question of Artin on generalizing the

principal ideal theorem In mathematics, the principal ideal theorem of class field theory, a branch of algebraic number theory, says that extending ideals gives a mapping on the class group of an algebraic number field to the class group of its Hilbert class field, w ...

and this was published in 1939. Iyanaga did publish many papers which arose through several courses such as

algebraic topology Algebraic topology is a branch of mathematics that uses tools from abstract algebra to study topological spaces. The basic goal is to find algebraic invariant (mathematics), invariants that classification theorem, classify topological spaces up t ...

functional analysis Functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit-related structure (for example, Inner product space#Definition, inner product, Norm (mathematics ...

, and

geometry Geometry (; ) is a branch of mathematics concerned with properties of space such as the distance, shape, size, and relative position of figures. Geometry is, along with arithmetic, one of the oldest branches of mathematics. A mathematician w ...

, which he taught. He became professor at the University of Tokyo in 1942, during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. Towards the end of the war, many Japanese cities were bombarded and he had to find refuge in the countryside. He was busy in editing textbooks from primary and secondary schools and he continued to give courses and organise seminars. After the end of the war, he joined the Science Council of Japan in 1947. He became a member of the Executive Committee of the International Mathematical Union in 1952. He was responsible for organizing the International Congress of Mathematicians in

Amsterdam Amsterdam ( , ; ; ) is the capital of the Netherlands, capital and Municipalities of the Netherlands, largest city of the Kingdom of the Netherlands. It has a population of 933,680 in June 2024 within the city proper, 1,457,018 in the City Re ...

in 1954, which he attended. He was President of the International Commission on Mathematical Instruction from 1957 to 1978. Iyanaga spent the year 1961-62 at the

University of Chicago The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

. He became Dean of the faculty of Science at the University of Tokyo in 1965, a position he held until his retirement in 1967. After his retirement, he was a visiting professor during 1967-68 at the

University of Nancy A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Uni ...

in France. From 1967 to 1977, he was a professor at

Gakushuin University is a private university in Mejiro, Toshima, Tokyo. The Gakushūin (or "Peers School") was established during the Meiji period to educate the children of the Japanese nobility, but back then the institution had only the primary and secondary ...

in Tokyo.

Honors and awards

Iyanaga received several honors and awards for his work. He received the Rising Sun from Japan in 1976. He was elected a member of the

Japan Academy The Japan Academy ( Japanese: 日本学士院, ''Nihon Gakushiin'') is an honorary organisation and science academy founded in 1879 to bring together leading Japanese scholars with distinguished records of scientific achievements. The Academy is ...

in 1978. He received the

Légion d'honneur The National Order of the Legion of Honour ( ), formerly the Imperial Order of the Legion of Honour (), is the highest and most prestigious French national order of merit, both military and Civil society, civil. Currently consisting of five cl ...

in 1980.

Publications

* *

References

External links

* * {{DEFAULTSORT:Iyanaga, Shokichi 1906 births 2006 deaths 20th-century Japanese mathematicians 21st-century Japanese mathematicians Japanese men centenarians Recipients of the Legion of Honour Recipients of the Order of the Rising Sun, 2nd class University of Tokyo alumni Academic staff of the University of Tokyo Academic staff of Nancy-Université Academic staff of Nagoya University Scientists from Tokyo Metropolis