Question: Nikolai Chebotaryov and Dmitri Egorov, have which occupation?

full_context: Document 1: Andrey Kolmogorov: Andrey Nikolaevich Kolmogorov (Russian: Андрей Николаевич Колмогоров ; ] , 25 April 1903 – 20 October 1987) was a 20th-century Soviet mathematician who made significant contributions to the mathematics of probability theory, topology, intuitionistic logic, turbulence, classical mechanics, algorithmic information theory and computational complexity.
Document 2: Nikolay Mitrofanovich Krylov: Nikolay Mitrofanovich Krylov (Russian: Никола́й Митрофа́нович Крыло́в , Ukrainian: Микола Митрофанович Крилов ) (29 November [O.S. 17 November] 1879 – May 11, 1955) was a Russian and Soviet mathematician known for works on interpolation, non-linear mechanics, and numerical methods for solving equations of mathematical physics.
Document 3: Eugene Dynkin: Eugene Borisovich Dynkin (Russian: Евге́ний Бори́сович Ды́нкин ; 11 May 1924 – 14 November 2014) was a Soviet and American mathematician. He has made contributions to the fields of probability and algebra, especially semisimple Lie groups, Lie algebras, and Markov processes. The Dynkin diagram, the Dynkin system, and Dynkin's lemma are named after him.
Document 4: Dmitri Egorov: Dmitri Fyodorovich Egorov (Russian: Дми́трий Фёдорович Его́ров ; December 22, 1869 – September 10, 1931) was a Russian and Soviet mathematician known for significant contributions to the areas of differential geometry and mathematical analysis. He was President of the Moscow Mathematical Society (1923 — 1930).
Document 5: 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 mathematical journal. The English translation is "Sbornik: Mathematics". It is also sometimes cited under the alternative name "Izdavaemyi Moskovskim Matematicheskim Obshchestvom" or its French translation "Recueil mathématique de la Société mathématique de Moscou", but the name "Recueil mathématique" is also used for an unrelated journal, "Mathesis". Yet another name, "Sovetskii Matematiceskii Sbornik", was listed in a statement in the journal in 1931 apologizing for the former editorship of Dmitri Egorov, who had been recently discredited for his religious views; however, this name was never actually used by the journal.
Document 6: Dmitri Anosov: Dmitri Victorovich Anosov (Russian: Дми́трий Ви́кторович Ано́сов ; November 30, 1936 – August 5, 2014) was a Soviet and Russian mathematician, known for his contributions to dynamical systems theory.
Document 7: Evgenii Georgievich D'yakonov: D'yakonov was a Ph.D. student of Sergei Sobolev. He worked at the Moscow State University. He authored over hundred papers and several books. D'yakonov was recognized for his pioneering work in the 60s–80s on efficient spectrally equivalent preconditioning for linear systems and eigenvalue problems. In the last decade, strengthened Sobolev spaces became D'yakonov's main topic of research, e.g., (D'yakonov, 2004).
Document 8: Chebotarev's density theorem: Chebotarev's density theorem in algebraic number theory describes statistically the splitting of primes in a given Galois extension "K" of the field formula_1 of rational numbers. Generally speaking, a prime integer will factor into several ideal primes in the ring of algebraic integers of "K". There are only finitely many patterns of splitting that may occur. Although the full description of the splitting of every prime "p" in a general Galois extension is a major unsolved problem, the Chebotarev density theorem says that the frequency of the occurrence of a given pattern, for all primes "p" less than a large integer "N", tends to a certain limit as "N" goes to infinity. It was proven by Nikolai Chebotaryov in his thesis in 1922, published in .
Document 9: Krylov–Bogolyubov theorem: In mathematics, the Krylov–Bogolyubov theorem (also known as the existence of invariant measures theorem) may refer to either of the two related fundamental theorems within the theory of dynamical systems. The theorems guarantee the existence of invariant measures for certain "nice" maps defined on "nice" spaces and were named after Russian-Ukrainian mathematicians and theoretical physicists Nikolay Krylov and Nikolay Bogolyubov who proved the theorems.
Document 10: Nicolai Reshetikhin: Nicolai Yuryevich Reshetikhin (Russian: Николай Юрьевич Решетихин , born October 10, 1958 in Leningrad, Soviet Union) is a mathematical physicist, currently a professor of mathematics at the University of California, Berkeley and a professor of mathematical physics at the University of Amsterdam. His research is in the fields of low-dimensional topology, representation theory, and quantum groups. His major contributions are in the theory of quantum integrable systems, in representation theory of quantum groups
Document 11: Grigori Perelman: Grigori Yakovlevich Perelman (Russian: Григо́рий Я́ковлевич Перельма́н ; ] ; born 13 June 1966) is a Russian mathematician. He made a contribution to Riemannian geometry and geometric topology.
Document 12: 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 theorem now known as Egorov's theorem.
Document 13: Mikhail Kravchuk: Mykhailo Pylypovych Kravchuk, also Krawtchouk (Ukrainian: Миха́йло Пили́пович Кравчу́к ) (September 27, 1892 – March 9, 1942), was a Soviet Ukrainian mathematician who, despite his early death, was the author of around 180 articles on mathematics.
Document 14: Nikolai Chebotaryov: Nikolai Grigorievich Chebotaryov (often spelled Chebotarov or Chebotarev, Russian: Никола́й Григо́рьевич Чеботарёв , Ukrainian: Микола Григорович Чоботарьов ) (15 June [O.S. 3 June] 1894 – 2 July 1947) was a noted Ukrainian and Soviet mathematician. He is best known for the Chebotaryov density theorem.
Document 15: 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, after Carlo Severini, an Italian mathematician, and Dmitri Egorov, a Russian physicist and geometer, who published independent proofs respectively in 1910 and 1911.
ground_truth: mathematician