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In memory of Shiing-Shen Chern, the International Mathematical Unionestablished the Chern Medal in 2010 to recognize "an individual whose accomplishments warrant the highest level of recognition for outstanding achievements in the field of mathematics".^[8]

Biography

Early Years in China

Chern was born in Xiushui County (秀水縣), Jiaxing, inZhejiang province. The year after his birth, China changed its regime from the Qing Dynasty to the Republic of China. He graduated from Xiushui Middle School (秀水中學) and subsequently moved toTianjin in 1922 to accompany his father. In 1926, after spending four years in Tianjin, Chern graduated from Fulun High School (扶輪中學).^[9]

At age 15, Chern entered the Faculty of Sciences of theNankai University in Tianjin, but had problems at the laboratory, so he studied mathematics, instead.^[10]Chern graduated with a Bachelor of Science degree in 1930.^[10]At Nankai, Chern's mentor was Li-Fu Chiang (姜立夫), a Harvard-trained geometer. Also at Nankai, he was heavily influenced by the physicist Rao Yutai (饶毓泰). Rao is today considered to be one of the founding fathers of modern Chinese informatics.

Chern went to Beiping (now Beijing) to work at the Tsing Hua University Department of Mathematics as a teaching assistant. At the same time he also registered at TsinghuaGraduate School as a student. He studied projective differential geometry under Prof. Sun Guangyuan, aUniversity of Chicago-trained geometer and logician who was also from Zhejiang. Sun is another mentor of Chern who is considered a founder of modern Chinese mathematics. In 1932, Chern published his first research article in the Tsing Hua University Journal. In the summer of 1934, Chern graduated from Tsinghua with a master's degree, the first ever master's degree in mathematics issued in China.^[9]

Chen-Ning Yang's father—Yang Ko-Chuen, another Chicago-trained professor at Tsing Hua, but specialising in algebra, also taught Chern. At the same time, Chern was Chen-Ning Yang's teacher of undergraduate maths at Tsinghua.

At Tsinghua, Hua Luogeng, also a mathematician, was Chern's colleague and roommate.

In 1932, Wilhelm Blaschke from the University of Hamburg visited Tsinghua and was impressed by Chern and his research.^[11]

In Europe

In 1934, Chern received a scholarship to study in the United States, but he wanted to study under well-known geometer Wilhelm Blaschke.^[10]Co-funded by Tsing Hua and the Chinese Foundation of Culture and Education, Chern went to continue his study in mathematics in Germany with a scholarship.^[10]Chern studied at the University of Hamburg and worked under Blaschke's guidance first on the geometry of webs then on the Cartan-Kähler theory. He obtained his Dr. rer.nat. (Doctor of Science, which is equivalent to PhD) degree in February, 1936.^[10]Blaschke recommended Chern to study in Paris.

It was at this time that he had to choose between the career of algebra in Germany under Emil Artin, and the career of geometry in France under Élie-Joseph Cartan. Chern was tempted by what he called the "organizational beauty" of Emil Artin's Algebra, but in the end, he decided to go to France in September 1936.^[12]He spent one year at the Sorbonne in Paris.

In August 1936, Chern watched the Summer Olympics in Berlin together with Hua Luogengwho paid Chern a brief visit. During that time, Hua was studying at the University of Cambridge in Britain.

In the summer of 1937, Chern accepted the invitation of Tsing Hua's University and returned to China.^[12]He was promoted to professor of mathematics at Tsing Hua. However, in August, the Marco Polo Bridge Incident(near Beijing) happened and theSecond Sino-Japanese Warstarted, Tsing Hua was forced to move away from Beijing to west China.^[13]Three universities including Peking University, Tsing Hua, and Nankai formed the National Southwestern Associated University (NSAU), and relocated to Kunming, Yunnan province. Chern never reached Beijing. In the same year, Hua Luogeng was promoted to professor of mathematics at Tsinghua.

In 1939, Chern married Shih-Ning Cheng, and the couple had two children by the names of Paul and May.^[13]

Short Stay in the USA

In July 1943, Chern went to the United States, and worked at the Institute for Advanced Study (IAS) in Princeton oncharacteristic classes in differential geometry. Shortly afterwards, he was invited bySolomon Lefschetz to be an editor of Annals of Mathematics.^[13]

First Return to China

Chern returned to Shanghai in 1945 to help found the Institute of Mathematics of theAcademia Sinica, which was later moved to Nanking^[13](then-capital of the Republic of China). Chern was the acting president of the institute. Wu Wenjun was Chern's graduate student at the institute.

In 1948, Chern was elected one of the first academicians of the Academia Sinica. He was the youngest academician elected (at age 37).

USA

By the end of 1948, Chern returned to the United States because of the Chinese Civil War.^[13]He then returned to the IAS.^[13]In 1949, Chern became professor of mathematics at the University of Chicago.^[13]Coincidentally, Ernest Preston Lane, former Chair at UChicago Department of Mathematics, was the doctoral advisor of Chern's undergraduate mentor at Tsinghua—Sun Guangyuan.

Chern moved to the University of California, Berkeley, in 1960.^[13]He worked and stayed there until he became an emeritus professor in 1979.^[14]In 1961, Chern became a naturalized citizen of the United States. In the same year, he was elected member of the United States National Academy of Sciences.^[15]

In 1964, Chern was a vice-president of American Mathematical Society (AMS).

Chern retired from Berkeley in 1981. He founded theMathematical Sciences Research Institute (MSRI) in 1981 and served as the director until 1984. Afterward he became the honorary director of the institute. MSRI now is one of the largest and most prominent mathematical institutes in the world.^[15]Shing-Tung Yau was one of his PhD students during this period.

Short Visits to China

The Shanghai Communiquéwas issued by the United States and the People's Republic of China on February 27, 1972. The relationship between these two nations started to normalise, and American citizens were allowed to visit P.R.China. In September 1972, Chern visited Beijing with his wife. During this period of time, Chern visited China 25 times, of which 14 were to his home province Zhejiang.

Chern founded the Nankai Institute for Mathematics (NKIM) at his alma mater Nankai in Tianjin. The institute was formally established in 1984 and fully opened in October 17, 1985. NKIM was renamed theChern Institute of Mathematicsin 2004 after Chern's death.

Final Years and Death

Based on Chern's advice, a mathematical research center was established in Taipei, Taiwan, whose co-operational partners are National Taiwan University, National Tsing Hua University and the Sinica Academia Institute of Mathematics.^[16]

Chern was also a director and advisor of the Center of Mathematical Sciences at Zhejiang University inHangzhou, Zhejiang.

From 2000 to his death, Chern lived in Tianjin, China. Chern died of heart failure at his home in Tianjin in 2004 at age 93.

Research

Chern's work extends over all the classic fields of differential geometry. It includes areas currently fashionable (theChern–Simons theory arising from a 1974 paper written jointly with Jim Simons), perennial (the Chern–Weil theory linking curvatureinvariants to characteristic classes from 1944, after theAllendoerfer–Weil paper of 1943 on the Gauss–Bonnet theorem), the foundational (Chern classes), and some areas such as projective differential geometry and websthat have a lower profile. He published results in integral geometry, value distribution theory of holomorphic functions, and minimal submanifolds.

He was a follower of Élie Cartan, working on the 'theory of equivalence' in his time in China from 1937 to 1943, in relative isolation. In 1954 he published his own treatment of the pseudogroup problem that is in effect the touchstone of Cartan's geometric theory. He used the moving frame method with success only matched by its inventor; he preferred incomplex manifold theory to stay with the geometry, rather than follow the potential theory. Indeed, one of his books is entitled "Complex Manifolds without Potential Theory". In the last years of his life, he advocated the study of Finsler geometry, writing several books and articles on the subject.

Honours and awards

Chern received numerous honors and awards in his life, including:

1970, Chauvenet Prize, of the Mathematical Association of America;
1975, National Medal of Science^[17]
1982, Humboldt Prize, Germany;
1983, Leroy P. Steele Prize, of the American Mathematical Society;
1984, Wolf Prize in Mathematics, Israel;
2002, Lobachevsky Medal;
2004 May, Shaw Prize in mathematical sciences, Hong Kong;^[18]
1948, Academician,Academia Sinica;
1950, Honorary Member,Indian Mathematical Society;
1961, Member, United States National Academy of Sciences;
1963, Fellow, American Academy of Arts and Sciences;
1971, Corresponding Member, Brazilian Academy of Sciences;
1983, Associate Founding Fellow, TWAS;
1985, Foreign Fellow, Royal Society of London, UK;
1986, Honorary Fellow,London Mathematical Society, UK;
1986, Corresponding Member, Academia Peloritana, Messina, Sicily;
1987, Honorary Life Member, New York Academy of Sciences;
1989, Foreign Member,Accademia dei Lincei, Italy;
1989, Foreign Member,Académie des sciences, France;
1989, Member, American Philosophical Society;
1994, Foreign Member,Chinese Academy of Sciences.

Chern was given a number of honorary degrees, including from The Chinese University of Hong Kong (LL.D. 1969),University of Chicago (D.Sc. 1969), ETH Zurich (Dr.Math. 1982), SUNY Stony Brook (D.Sc. 1985), TU Berlin (Dr.Math. 1986), his alma mater Hamburg (D.Sc. 1971) and Nankai (honorary doctorate, 1985), etc.

Chern was also granted numerous honorary professorships, including atPeking University (Beijing, 1978), his alma mater Nankai (Tianjin, 1978), Chinese Academy of Sciences Institute of Systems Science (Beijing, 1980), Jinan University(Guangzhou, 1980), Chinese Academy of Sciences Graduate School (1984), Nanjing University (Nanjing, 1985), East China Normal University(Shanghai, 1985), USTC (Hefei, 1985), Beijing Normal University(1985), Zhejiang University(Hangzhou, 1985), Hangzhou University (1986, the university was merged into Zhejiang University in 1998), Fudan University (Shanghai, 1986),Shanghai University of Technology (1986, the university was merged to establish Shanghai University in 1994), Tianjin University (1987),Tohoku University (Sendai, Japan, 1987), etc.

Publication

Shiing Shen Chern, Topics in Differential Geometry, Princeton 1951
Shiing Shen Chern Differential Manifolds 1953 University of Chicago
Shiing Shen Chern, Complex Manifolds University of Chicago, 1956
Shiing Shen Chern:Complex manifolds without potential theory
Shiing Shen Chern, Minimal Sumanifolds in a Riemannian Manifold University of Kansas 1968
Bao, David Dai-Wai; Chern, Shiing-Shen; Shen, Zhongmin Finsler Geometry
Zhongmin Shen, Shiing-shen Chern, Riemann Finsler Geometry
Shiing Shen Chern, Selected Papers, Vol I-IV, Springer

Namesake

The asteroid 29552 Chernis named after him;
The Chern Medal, of theInternational Mathematical Union (IMU);^[19]
The Shiing-Shen Chern Prize (陳省身獎), of the Association of Chinese Mathematicians;
The Chern Institute of Mathematics at Nankai University, Tianjin, China;
The Chern Lectures, and the Shiing-Shen Chern Chair in Mathematics, both at the Department of Mathematics, UC Berkeley.^[20]

Family

His wife, Shih-ning Cheng(Chinese: 鄭士寧; pinyin:Zheng Shining), whom he married in 1939, died in 2000. He also had a daughter, May Chu (Chinese: 陳璞; pinyin: Chen Pu), wife of the physicist Chu Ching-wu, and a son named Paul (pinyin: Chen Bolong).

Transliteration and pronunciation

Chern's surname is a common Chinese surname which is now usually spelt Chen. The unusual spelling "Chern" is atransliteration in the oldGwoyeu Romatzyh (GR)romanization for Mandarin Chinese used in the early twentieth century China. It uses special spelling rules to indicate different tones of Mandarin, which is a tonal language with four tones. The silent r in "Chern" indicates asecond-tone syllable, written "Chén" in pinyin but in practice often written by non-Chinese without the tonal mark. In GR the spelling of his given name "Shiing-Shen" indicates a third tone for Shiing and a first tone for Shen, which are equivalent to the syllables "Xǐngshēn" inpinyin.

In English, Chern pronounced his name "Churn" (), and this pronunciation is now universally accepted among English-speaking mathematicians and physicists.

See also

References