View source for Chiungtze C. Tsen (nonfiction)

[[File:Chiungtze C. Tsen 1932.jpg|thumb|Chiungtze C. Tsen; 1932 near Göttingen.]]'''Chiungtze C. Tsen''' (Chinese: 曾炯之; pinyin: Zēng Jiǒngzhī; Wade–Giles: Tseng Chiung-chih, April 2, 1898 – October 1, 1940) was a Chinese mathematician.

== Biography ==

Tsen was born in Nanchang, Jiangxi, 

He was one of [[Emmy Noether (nonfiction)|Emmy Noether]]'s students at the University of Göttingen. He returned to China in 1935. After the full-scale Japanese invasion of China in 1937, he fled and eventually settled in Xikang, where he became a professor at the newly-founded National Xikang Institute of Technology. He died of a stomach ulcer in Xichang, Xikang on October 1, 1940, and a memorial service was held on November 18, 1940. (Many Chinese sources mistakenly give his date of death as November 1940.)

== Career ==

One of his research interests was [[Quasi-algebraically closed field (nonfiction)|quasi-algebraic closure]]. In that area, in 1933 he proved [[Tsen's theorem (nonfiction)|Tsen's theorem]], which states that a function field K of an [[Algebraic curve (nonfiction)|algebraic curve]] over an algebraically closed field is quasi-algebraically closed (i.e., C1). This implies that the [[Brauer group (nonfiction)|Brauer group]] of any such field vanishes, and more generally that all the [[Galois cohomology (nonfiction)|Galois cohomology]] groups H i(K, K*) vanish for i ≥ 1. This result is used to calculate the [[Étale cohomology (nonfiction)|étale cohomology]] groups of an algebraic curve.

In 1936 he introduced the [[Tsen rank (nonfiction)|Tsen rank]] of a field, describing conditions under which a system of [[Algebraic equation (nonfiction)|polynomial equations]] must have a solution in the [[Field (nonfiction)|field]].

He proved Tsen's theorem. 

== In the News ==

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== Fiction cross-reference ==

* [[Crimes against mathematical constants]]
* [[Gnomon algorithm]]
* [[Gnomon Chronicles]]
* [[Mathematician]]
* [[Mathematics]]

== Nonfiction cross-reference ==

* [[Mathematician (nonfiction)]]
* [[Mathematics (nonfiction)]]
* [[Emmy Noether (nonfiction)]]

== External links ==

* [https://en.wikipedia.org/wiki/Chiungtze_C._Tsen Chiungtze C. Tsen] @ Wikipedia
* [https://en.wikipedia.org/wiki/Tsen_rank Tsen rank] @ Wikipedia
* [https://en.wikipedia.org/wiki/Tsen%27s_theorem Tsen's theorem] @ Wikipedia

[[Category:Nonfiction (nonfiction)]]

{{Categories: Chiungtze C. Tsen}}