Chen Jingrun (; 22 May 1933 – 19 March 1996), also known as Jing-Run Chen, was a Chinese

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, structure, space, models, and change. History On ...

who made significant contributions to

number theory Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure mathematics devoted primarily to the study of the integers and arithmetic function, integer-valued functions. German mathematician Carl Friedrich Gauss (1777� ...

, including

Chen's theorem In number theory, Chen's theorem states that every sufficiently large parity (mathematics), even number can be written as the sum of either two prime number, primes, or a prime and a semiprime (the product of two primes). History The theorem wa ...

and the

Chen prime A prime number ''p'' is called a Chen prime if ''p'' + 2 is either a prime or a product of two primes (also called a semiprime). The even number 2''p'' + 2 therefore satisfies Chen's theorem. The Chen primes are named after Chen Jingru ...

Life and career

Chen was the third son in a large family from

Fuzhou Fuzhou (; , Fuzhounese: Hokchew, ''Hók-ciŭ''), alternately romanized as Foochow, is the capital and one of the largest cities in Fujian province, China. Along with the many counties of Ningde, those of Fuzhou are considered to constitute t ...

Fujian Fujian (; alternately romanized as Fukien or Hokkien) is a province on the southeastern coast of China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its capi ...

, China. His father was a postal worker. Chen Jingrun graduated from the Mathematics Department of

Xiamen University Xiamen University (; Southern Min: ''Ē-mn̂g-toā-o̍h''), colloquially known as Xia Da (; Southern Min: ''Hā-tāi''), is a national public research university in Xiamen, Fujian, China. Founded in 1921 by Tan Kah Kee, a Chinese patriotic exp ...

in 1953. His advisor at the

Chinese Academy of Sciences The Chinese Academy of Sciences (CAS); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Republ ...

was

Hua Luogeng Hua Luogeng or Hua Loo-Keng (; 12 November 1910 – 12 June 1985) was a Chinese mathematician and politician famous for his important contributions to number theory and for his role as the leader of mathematics research and education in the Peop ...

. His work on the

twin prime conjecture A twin prime is a prime number that is either 2 less or 2 more than another prime number—for example, either member of the twin prime pair (41, 43). In other words, a twin prime is a prime that has a prime gap of two. Sometimes the term ''twin pr ...

Waring's problem In number theory, Waring's problem asks whether each natural number ''k'' has an associated positive integer ''s'' such that every natural number is the sum of at most ''s'' natural numbers raised to the power ''k''. For example, every natural num ...

Goldbach's conjecture Goldbach's conjecture is one of the oldest and best-known unsolved problems in number theory and all of mathematics. It states that every even natural number greater than 2 is the sum of two prime numbers. The conjecture has been shown to hold ...

and

Legendre's conjecture Legendre's conjecture, proposed by Adrien-Marie Legendre, states that there is a prime number between n^2 and (n+1)^2 for every positive integer n. The conjecture is one of Landau's problems (1912) on prime numbers; , the conjecture has neither ...

led to progress in

analytic number theory In mathematics, analytic number theory is a branch of number theory that uses methods from mathematical analysis to solve problems about the integers. It is often said to have begun with Peter Gustav Lejeune Dirichlet's 1837 introduction of Diric ...

. In a 1966 paper he proved what is now called

: every

sufficiently large In the mathematical areas of number theory and analysis, an infinite sequence or a function is said to eventually have a certain property, if it doesn't have the said property across all its ordered instances, but will after some instances have pa ...

even number can be written as the sum of a prime and a

semiprime In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so the semiprimes include the squares of prime numbers. Because there are infinitely many prime nu ...

(the product of two primes) – e.g., 100 = 23 + 7·11. Despite being persecuted during the

Cultural Revolution The Cultural Revolution, formally known as the Great Proletarian Cultural Revolution, was a sociopolitical movement in the People's Republic of China (PRC) launched by Mao Zedong in 1966, and lasting until his death in 1976. Its stated goal ...

, he expanded his proof in the 1970s. After the end of the Cultural Revolution, Xu Chi wrote a biography of Chen entitled ''Goldbach's Conjecture'' (). First published in ''

People's Literature ''People's Literature'' (《人民文学》''Renmin wenxue'') is the oldest continuously published literary magazine in China, and the first literary magazine published in Communist China. Established in 1949, the magazine is published by the Peo ...

'' in January 1978, it was reprinted on the ''

People's Daily The ''People's Daily'' () is the official newspaper of the Central Committee of the Chinese Communist Party (CCP). The newspaper provides direct information on the policies and viewpoints of the CCP. In addition to its main Chinese-language ...

'' a month later and became a national sensation. Chen became a household name in China and received a sackful of love letters from all over the country within two months. Chen died of complications of

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity ...

on March 19, 1996, at the age of 63 years.

Legacy

The

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

7681 Chenjingrun, discovered in 1996, was named after him. In 1999, China issued an 80-cent postage stamp, titled ''The Best Result of Goldbach Conjecture,'' with a silhouette of Chen and the inequality: :

P_x(1, 2) \ge \frac.

Several statues in China have been built in memory of Chen. At Xiamen University, the names of Chen and four other mathematicians —

Peter Gustav Lejeune Dirichlet Johann Peter Gustav Lejeune Dirichlet (; 13 February 1805 – 5 May 1859) was a German mathematician who made deep contributions to number theory (including creating the field of analytic number theory), and to the theory of Fourier series and ...

Matti Jutila Matti Ilmari Jutila (born 1943) is a mathematician and a professor emeritus at the University of Turku. He researches in the field of analytic number theory. Education and career Jutila completed a doctorate at the University of Turku in 1970, ...

Yuri Linnik Yuri Vladimirovich Linnik (russian: Ю́рий Влади́мирович Ли́нник; January 8, 1915 – June 30, 1972) was a Soviet mathematician active in number theory, probability theory and mathematical statistics. Linnik was born in B ...

, and

Pan Chengdong Pan Chengdong ( zh, c=潘承洞, p=Pān Chéngdòng; 26 May 1934 – 27 December 1997) was a Chinese mathematician who made numerous contributions to number theory Number theory (or arithmetic or higher arithmetic in older usage) is a br ...

— are inscribed in the marble slab behind Chen's statue (see image).

Works

*J.-R. Chen, On the representation of a large even integer as the sum of a prime and a product of at most two primes, Sci. Sinica 16 (1973), 157–176. *Chen, J.R, "On the representation of a large even integer as the sum of a prime and the product of at most two primes". hineseJ. Kexue Tongbao 17 (1966), 385–386. *"Fundamental Number Theory"

References

*Pan Chengdong and Wang Yuan
''Chen Jingrun: a brief outline of his life and works'', Acta Math. Sinica (NS) 12 (1996) 225–233.

External links

*

at th

{{DEFAULTSORT:Chen, Jingrun 1933 births 1996 deaths 20th-century Chinese mathematicians Members of the Chinese Academy of Sciences Number theorists Educators from Fujian Guizhou Nationalities University faculty Henan University faculty Xiamen University faculty Qingdao University faculty Huazhong University of Science and Technology faculty Fujian Normal University faculty People from Fuzhou Mathematicians from Fujian Xiamen University alumni Delegates to the 4th National People's Congress Delegates to the 5th National People's Congress Delegates to the 6th National People's Congress