Theodor Estermann (5 February 1902 – 29 November 1991) was a German-born American

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 ...

, working in the field of

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 ...

. The

Estermann measure In plane geometry the Estermann measure is a number defined for any bounded convex set describing how close to being centrally symmetric it is. It is the ratio of areas between the given set and its smallest centrally symmetric convex superset. It ...

, a measure of the

central symmetry In geometry, a point reflection (point inversion, central inversion, or inversion through a point) is a type of isometry of Euclidean space. An object that is invariant under a point reflection is said to possess point symmetry; if it is invari ...

of a

convex set In geometry, a subset of a Euclidean space, or more generally an affine space over the reals, is convex if, given any two points in the subset, the subset contains the whole line segment that joins them. Equivalently, a convex set or a convex r ...

in the

Euclidean plane In mathematics, the Euclidean plane is a Euclidean space of dimension two. That is, a geometric setting in which two real quantities are required to determine the position of each point ( element of the plane), which includes affine notions of ...

, is named after him. He was born in

Neubrandenburg Neubrandenburg (lit. ''New Brandenburg'', ) is a city in the southeast of Mecklenburg-Vorpommern, Germany. It is located on the shore of a lake called Tollensesee and forms the urban centre of the Mecklenburg Lakeland. The city is famous for its ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

, "to keen

Zionists Zionism ( he, צִיּוֹנוּת ''Tsiyyonut'' after ''Zion'') is a nationalist movement that espouses the establishment of, and support for a homeland for the Jewish people centered in the area roughly corresponding to what is known in Jew ...

who named him in honour of

Herzl Herzl is both a given name and a surname. Notable people with the name include: Given name: *Herzl Berger *Herzl Bodinger *Herzl Rosenblum *Herzl Yankl Tsam Surname: *Theodor Herzl See also *Mount Herzl *''Herzl (play) ''Herzl'' is a 1976 play w ...

." His doctorate, completed in 1925, was supervised by

Hans Rademacher Hans Adolph Rademacher (; 3 April 1892, Wandsbeck, now Hamburg-Wandsbek – 7 February 1969, Haverford, Pennsylvania, USA) was a German-born American mathematician, known for work in mathematical analysis and number theory. Biography Rademacher r ...

. He spent most of his career at

University College London , mottoeng = Let all come who by merit deserve the most reward , established = , type = Public research university , endowment = £143 million (2020) , budget = ...

, eventually as a

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...

Heini Halberstam Heini Halberstam (11 September 1926 oreen Halberstam, wife– 25 January 2014) was a Czech-born British mathematician, working in the field of analytic number theory. He is remembered in part for the Elliott–Halberstam conjecture from 1968. ...

Klaus Roth Klaus Friedrich Roth (29 October 1925 – 10 November 2015) was a German-born British mathematician who won the Fields Medal for proving Roth's theorem on the Diophantine approximation of algebraic numbers. He was also a winner of the De M ...

and Robert Charles Vaughan were Ph.D. students of his. Though Estermann left Germany in 1929, before the Nazis seized power in 1933, some historians count him among the early emigrants who fled Nazi Germany.

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LMS obituary
1902 births 1991 deaths Academics of University College London 20th-century German mathematicians People from Neubrandenburg Jewish scientists Jewish emigrants from Nazi Germany to the United Kingdom {{germany-mathematician-stub