Editing Chen Jingrun

{{Short description|Chinese number theorist}}
{{Use dmy dates|date=October 2019}}
{{family name hatnote|[[Chen (surname)|Chen]]|lang=Chinese}}
{{Infobox scientist
|name                    = Chen Jingrun
|image                   = Chen Jingrun.jpg
|birth_date              = 22 May 1933
|birth_place             = [[Fuzhou]], [[Fujian]], China
|death_date              = {{death date and age|df=yes|1996|3|19|1933|5|22}}
|death_place             = Beijing, China
|field                   = [[Mathematics]]
|alma_mater              = [[Chinese Academy of Sciences]]<br />[[Xiamen University]]
|doctoral_advisor        = [[Hua Luogeng]]
|known_for               = [[Chen's theorem]], [[Chen prime]]
|module = {{Chinese|child=yes|t=陳景潤|s=陈景润|p=Chén Jǐngrùn|w=Chʻen<sup>2</sup> Ching<sup>3</sup>-jun<sup>4</sup>|mi={{IPAc-cmn|ch|en|2|-|j|ing|3|.|r|un|4}}|buc=Dìng Gīng-nông}}
}}
'''Chen Jingrun''' ({{zh|s=陳景潤}}; 22 May 1933 – 19 March 1996), also known as '''Jing-Run Chen''', was a Chinese [[mathematician]] who made significant contributions to [[number theory]], including [[Chen's theorem]] and the [[Chen prime]].

==Life and career==
Chen was the third son in a large family from [[Fuzhou]], [[Fujian]], China.  His father was a postal worker. Chen Jingrun graduated from the Mathematics Department of [[Xiamen University]] in 1953. His advisor at the [[Chinese Academy of Sciences]] was [[Hua Luogeng]].

His work on the [[twin prime conjecture]], [[Waring's problem]], [[Goldbach's conjecture]] and [[Legendre's conjecture]] led to progress in [[analytic number theory]]. In a 1966 paper he [[mathematical proof|proved]] what is now called [[Chen's theorem]]: every [[sufficiently large]] even number can be written as the sum of a prime and a [[semiprime]] (the product of two primes) – e.g., 100&nbsp;=&nbsp;23&nbsp;+&nbsp;7·11.<ref name="Song2014">{{cite book|last=Song|first=Yuwu|title=Biographical Dictionary of the People's Republic of China|url=https://books.google.com/books?id=DGbyzKLVh30C&pg=PA35|year=2014|publisher=McFarland|isbn=978-1-4766-0298-1|page=35}}</ref> Despite being persecuted during the [[Cultural Revolution]], he expanded his proof in the 1970s.<ref>{{Cite web|url=http://www.chinawriter.com.cn/n1/2017/1218/c405173-29711930.html|title=徐迟报告文学的突破、经验及警示意义|author=Shi Xingze 石兴泽|date=18 December 2017|publisher=China Writers' Association|language=zh|url-status=live|archive-url=https://web.archive.org/web/20191026035456/http://www.chinawriter.com.cn/n1/2017/1218/c405173-29711930.html |archive-date=26 October 2019 |access-date=4 October 2019}}</ref>

After the end of the Cultural Revolution, [[Xu Chi]] wrote a biography of Chen entitled ''Goldbach's Conjecture'' ({{lang|zh|哥德巴赫猜想}}). First published in ''[[People's Literature]]'' in January 1978, it was reprinted on the ''[[People's Daily]]'' 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.<ref>{{Cite web|url=http://mjlsh.usc.cuhk.edu.hk/Book.aspx?cid=4&tid=3821|title=揭开诗人徐迟跳楼之谜|author=Zhang Shouren 张守仁|date=December 2016|publisher=Chinese University of Hong Kong|language=zh|url-status=live|archive-url=https://web.archive.org/web/20201107175338/http://mjlsh.usc.cuhk.edu.hk/Book.aspx?cid=4&tid=3821 |archive-date=7 November 2020 |access-date=4 October 2019}}</ref>

Chen died of complications of [[pneumonia]] on 19 March 1996, at the age of 62 years.<ref>{{Cite journal|url=https://thejns.org/focus/view/journals/neurosurg-focus/41/1/article-pE11.xml|doi = 10.3171/2016.2.FOCUS1595|title = Chen Jingrun, China's famous mathematician: Devastated by brain injuries on the doorstep to solving a fundamental mathematical puzzle|year = 2016|last1 = Lei|first1 = Ting|last2 = Belykh|first2 = Evgenii|last3 = Dru|first3 = Alexander B.|last4 = Yagmurlu|first4 = Kaan|last5 = Elhadi|first5 = Ali M.|last6 = Nakaji|first6 = Peter|last7 = Preul|first7 = Mark C.|journal = Neurosurgical Focus|volume = 41|issue = 1|pages = E11|pmid = 27364253|doi-access = free}}</ref>

==Legacy==
[[File:A statue of Chen Jingrun.JPG|right|thumb|Chen's statue at [[Xiamen University]], China.|250px]]
The [[asteroid]] [[7681 Chenjingrun]], discovered in 1996, was named after him.<ref name="Song2014" />

In 1999, China issued an 80-cent postage stamp, titled ''The Best Result of Goldbach Conjecture,'' with a silhouette of Chen and the inequality:<ref name="Song2014" />

: <math>P_x(1, 2) \ge \frac{0.67xC_x}{(\log x)^2}.</math>

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]], [[Matti Jutila]], [[Yuri Linnik]], and [[Pan Chengdong]] — 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". [Chinese] J. Kexue Tongbao 17 (1966), 385–386.
*"Fundamental Number Theory"

==References==
{{reflist}}
*Pan Chengdong and [[Wang Yuan (mathematician)|Wang Yuan]], [https://web.archive.org/web/20070715052529/http://www.numbertheory.org/obituaries/OTHERS/chen/ ''Chen Jingrun: a brief outline of his life and works'', Acta Math. Sinica (NS) '''12''' (1996) 225–233.]

==External links==
*{{MathGenealogy|id=25269}}
*[https://web.archive.org/web/20040401112756/http://www.math.ac.cn/Chinese/B/Chenjr/Chenjr.htm Chen's home page]{{in lang|zh}} at the [https://web.archive.org/web/20040401122341/http://www.math.ac.cn/English/2/History.htm Chinese Institute of Mathematics].

{{Authority control}}

{{DEFAULTSORT:Chen, Jingrun}}

[[Category:1933 births]]
[[Category:1996 deaths]]
[[Category:20th-century Chinese mathematicians]]
[[Category:Academic staff of Guizhou Nationalities University]]
[[Category:Academic staff of Henan University]]
[[Category:Academic staff of Huazhong University of Science and Technology]]
[[Category:Academic staff of Qingdao University]]
[[Category:Academic staff of Xiamen University]]
[[Category:Academic staff of Fujian Normal University]]
[[Category:Delegates to the 4th National People's Congress]]
[[Category:Delegates to the 5th National People's Congress]]
[[Category:Delegates to the 6th National People's Congress]]
[[Category:Writers from Fuzhou]]
[[Category:Educators from Fujian]]
[[Category:Mathematicians from Fujian]]
[[Category:Members of the Chinese Academy of Sciences]]
[[Category:Number theorists]]
[[Category:People from Fuzhou]]
[[Category:Xiamen University alumni]]