Dmitri Fyodorovich Egorov (russian: Дми́трий Фёдорович Его́ров; December 22, 1869 – September 10, 1931) was a

Russian Russian(s) refers to anything related to Russia, including: *Russians (, ''russkiye''), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *Rossiyane (), Russian language term for all citizens and peo ...

and

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

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 ...

known for contributions to the areas of

differential geometry Differential geometry is a mathematical discipline that studies the geometry of smooth shapes and smooth spaces, otherwise known as smooth manifolds. It uses the techniques of differential calculus, integral calculus, linear algebra and multili ...

and

mathematical analysis Analysis is the branch of mathematics dealing with continuous functions, limit (mathematics), limits, and related theories, such as Derivative, differentiation, Integral, integration, measure (mathematics), measure, infinite sequences, series (m ...

. He was President of the

Moscow Mathematical Society The Moscow Mathematical Society (MMS) is a society of Moscow mathematicians aimed at the development of mathematics in Russia. It was created in 1864, and Victor Vassiliev is the current president. History The first meeting of the society wa ...

(1923–1930).

Life

Egorov held spiritual beliefs to be of great importance, and openly defended the Church against Marxist supporters after the

Russian Revolution The Russian Revolution was a period of Political revolution (Trotskyism), political and social revolution that took place in the former Russian Empire which began during the First World War. This period saw Russia abolish its monarchy and ad ...

. He was elected president of the

in 1921, and became director of the Institute for Mechanics and Mathematics at

Moscow State University M. V. Lomonosov Moscow State University (MSU; russian: Московский государственный университет имени М. В. Ломоносова) is a public research university in Moscow, Russia and the most prestigious ...

in 1923. He also edited the journal ''

Matematicheskii Sbornik ''Matematicheskii Sbornik'' (russian: Математический сборник, abbreviated ''Mat. Sb.'') is a peer reviewed Russian mathematical journal founded by the Moscow Mathematical Society in 1866. It is the oldest successful Russian ma ...

'' of the Moscow Mathematical Society. However, because of Egorov's stance against the repression of the

Russian Orthodox Church , native_name_lang = ru , image = Moscow July 2011-7a.jpg , imagewidth = , alt = , caption = Cathedral of Christ the Saviour in Moscow, Russia , abbreviation = ROC , type ...

, he was dismissed from the Institute in 1929 and publicly rebuked. In 1930 he was arrested and imprisoned as a "religious sectarian", and soon after was expelled from the

. Upon imprisonment, Egorov began a

hunger strike A hunger strike is a method of non-violent resistance in which participants fast as an act of political protest, or to provoke a feeling of guilt in others, usually with the objective to achieve a specific goal, such as a policy change. Most ...

until he was taken to the prison hospital, and eventually to the house of fellow mathematician

Nikolai Chebotaryov Nikolai Grigorievich Chebotaryov (often spelled Chebotarov or Chebotarev, uk, Мико́ла Григо́рович Чеботарьо́в, russian: Никола́й Григо́рьевич Чеботарёв) ( – 2 July 1947) was a Ukrainian ...

where he died. He was buried in

Arskoe Cemetery Arskoe Cemetery is the central necropolis in Kazan, and is located in the city's Vakhitovsky City District, to the northeast of Kazan's centre in Tatarstan, Russia. The cemetery church was built in 1796, and was the only church in Kazan to rema ...

Kazan Kazan ( ; rus, Казань, p=kɐˈzanʲ; tt-Cyrl, Казан, ''Qazan'', IPA: ɑzan is the capital and largest city of the Republic of Tatarstan in Russia. The city lies at the confluence of the Volga and the Kazanka rivers, covering a ...

Research work

Egorov studied

potential Potential generally refers to a currently unrealized ability. The term is used in a wide variety of fields, from physics to the social sciences to indicate things that are in a state where they are able to change in ways ranging from the simple re ...

surfaces and triply

orthogonal In mathematics, orthogonality is the generalization of the geometric notion of ''perpendicularity''. By extension, orthogonality is also used to refer to the separation of specific features of a system. The term also has specialized meanings in ...

systems, and made contributions to the broader areas of

and

integral equation In mathematics, integral equations are equations in which an unknown Function (mathematics), function appears under an integral sign. In mathematical notation, integral equations may thus be expressed as being of the form: f(x_1,x_2,x_3,...,x_n ; ...

s. His work influenced that of

Jean Gaston Darboux Jean-Gaston Darboux FAS MIF FRS FRSE (14 August 1842 – 23 February 1917) was a French mathematician. Life According this birth certificate he was born in Nîmes in France on 14 August 1842, at 1 am. However, probably due to the midni ...

on differential geometry and

. A theorem in

real analysis In mathematics, the branch of real analysis studies the behavior of real numbers, sequences and series of real numbers, and real functions. Some particular properties of real-valued sequences and functions that real analysis studies include converg ...

and integration theory,

Egorov's Theorem In measure theory, an area of mathematics, Egorov's theorem establishes a condition for the uniform convergence of a pointwise convergent sequence of measurable functions. It is also named Severini–Egoroff theorem or Severini–Egorov theorem, a ...

, is named after him.He published a proof of this theorem in the short paper , and the result become widely acknowledged under his name.

Carlo Severini Carlo Severini (10 March 1872 – 11 May 1951) was an Italian mathematician: he was born in Arcevia (Province of Ancona) and died in Pesaro. Severini, independently from Dmitri Fyodorovich Egorov, proved and published earlier a proof of the the ...

had published a proof of the same result a year before, in the paper ; however, the work of Severini was unnoticed until

Leonida Tonelli Leonida Tonelli (19 April 1885 – 12 March 1946) was an Italian mathematician, noted for creating Tonelli's theorem, a variation of Fubini's theorem, and for introducing semicontinuity methods as a common tool for the direct method in the calc ...

recalled attention on it (see the entry about

for further details).

Works

*, available at Gallica.

Notes

Bibliography

*. *.

External links

* {{DEFAULTSORT:Egorov, Dimitri Egorov, Dmitri Egorov, Dmitri Egorov, Dmitri Egorov, Dmitri Corresponding Members of the Russian Academy of Sciences (1917–1925) Corresponding Members of the USSR Academy of Sciences Honorary Members of the USSR Academy of Sciences Egorov, Dmitri Egorov, Dmitri Egorov, Dmitri Egorov, Dmitri Professorships at the Imperial Moscow University Imperial Moscow University alumni Burials at Arskoe Cemetery