100 years have passed on May 10 since the birthday of academician Sadi Khasanovich Sirojiddinov, the well-known Uzbek mathematician, well-known scientist in the field of theory of probability and mathematical statistics, a kind and passionate teacher, who made a great contribution to the development of mathematics in Uzbekistan.

Sadi Khasanovich Sirojiddinov was born on May 10, 1920 in the city of Kokand. In 1942 he graduated from the Central Asian State University (now the National University of Uzbekistan named after Mirzo Ulugbek) with honors. He was called up for active military service that year. In 1944, Sadi Khasanovich entered graduate school and in 1947 defended his dissertation (his supervisor was Academician V.I. Romanovsky, who made a significant contribution to the formation of Sadi Khasanovich as a scientist and a person). From 1949 to 1952, Sadi Khasanovich studied at the Institute of Mathematics in Moscow named after VA Steklov under the guidance of the famous mathematician of the XX century, academician Andrei Nikolaevich Kolmogorov, and in 1953 he defended his doctoral dissertation at the same institute. After defending his dissertation, on the recommendation of his teacher A.N.Kolmogorov, Sadi Khasanovich worked as a professor at Moscow State University from 1953 to 1956. Upon his return to Tashkent in 1957, Sadi Khasanovich was appointed a director of the Institute of Mathematics of the Academy of Sciences of the Republic of Uzbekistan (1957-1966). In 1956 he was elected a corresponding member of the Academy of Sciences of Uzbekistan, and in 1966 he was elected an academician. Academician S.Kh. Sirojiddinov headed the Theory of Probability Department and Mathematical Statistics of Tashkent State University in 1958-1988, worked in the position of the rector of Tashkent State University (1966-1971 and 1983-1987), and vice-president of the Academy of Sciences of the Republic of Uzbekistan (1971-1983).

After returning from Moscow, S.Kh. Sirojiddinov began to implement his grand plans. He said that his main task was to revive the creative activity of mathematicians in Uzbekistan, to bring them to the forefront of science in terms of relevance of research topics and the importance of the results obtained, to train highly qualified personnel (doctors and candidates of science).

At the same time, he was passionate about the development of mathematics in all schools and universities in the country. S.Kh. Sirojiddinov made a significant contribution to the development of theory of probability and mathematical statistics, mathematical analysis, the history of mathematics in Central Asia, in short, almost all areas of mathematics in Uzbekistan.

At the initiative and with the help of S.Kh.Sirojiddinov, many young scientists were sent to research institutes and universities in Moscow, Leningrad (now St. Petersburg), Novosibirsk, Kiev for internships or postgraduate studies. allowed to expand and to enter new scientific directions.

S.Kh. Sirojiddinov‘s high academic reputation, personal contacts, and close friendships with leading mathematicians in research centers and universities played a major role in carrying out this work.

At the same time, the expansion of international scientific relations, the promotion of the results of mathematical research in Uzbekistan, their publication in prestigious journals in the 60-90s of the last century yielded positive results. This period was characterized for S.X. Sirojiddinov by the rise of mathematical creativity, the emergence of the spirit of scientific collectivism, the emergence of new areas of research.

Under the leadership and active participation of S.Kh.Sirojiddinov, a comprehensive study of the history of mathematics in Central Asia, which was widely recognized by experts, was conducted. Due to this, Tashkent became one of the leading centers of historical and mathematical research.

Speaking about the role of S.Kh. Sirojiddinov, it is necessary to mention his care for school mathematics in the development of mathematics in Uzbekistan. He deeply understood that the foundation of the building of mathematical sciences lay in school mathematics. Since 1962, he founded the organization of the annual Republican Mathematical Olympiads in Uzbekistan.

S.Kh. Sirojiddinov had a positive influence on the formation of many mathematicians in the Central Asian republics. The range of scientists who grew up under his influence was very wide, and under his direct leadership, more than 10 doctors of sciences and more than 40 candidates of sciences were trained.

The III Soviet-Japanese Symposium on the Theory of Probability (1975) and the First World Congress of the Bernoulli Society of Mathematical Statistics and the Theory of Probability (1986) were held in Tashkent in recognition of the achievements of mathematicians led by S.Kh. Sirojiddinov. To make such a big congress a success, S.Kh. Sirojiddinov dedicated the last years of his life. His scientific and organizational work is traditionally called the "Fergana Colloquium" - a conference on the limit theorems of the theory of probability and their applications. The Fergana Colloquium was held in 1962, 1972, and 1983 during the life of Sadi Khasanovich, and they became important events for specialists in the field of theory of probability and mathematical statistics. The next four colloquiums in 1995, 2005, 2011 and 2015 were dedicated to the memory of S.Kh. Sirojiddinov. Sadi Khasanovich was a member of the organizing committee of dozens of international scientific conferences and symposiums and delivered lectures. Among them: the meeting of the International Institute of Statistics (1957, The Hague, Netherlands), the International Congress of Mathematicians (1958, Edinburgh, Scotland), the symposium on the study of time series (1962, Provence, USA), the International Institute of Statistics (1966, The Hague, The Netherlands), International Congress of Mathematicians (1966, Moscow), Symposium of the International Association of Universities (1970, Canada; 1975, Canada; 1985, USA), II Japan-Soviet Symposium on the Theory of Probability (1972, Kyoto, Japan) , I, II, III, IV International Conferences on the Theory of Probability and Mathematical Statistics (1973, 1977, 1981, 1981, Vilnius, Lithuania), Meeting of European Statisticians (1981, Warsaw, Poland), V Japan-Soviet Conference on the Theory of Probability symposium (1986, Tokyo, Japan) and others. He was invited to give lectures at many foreign universities (India, Czechoslovakia, Sweden, Germany, etc.).

As a proof of the recognition of S.Kh. Sirojiddinov‘s scientific achievements was his election as a member of the International Institute of Statistics (The Hague, 1966) and the Moscow Society of Mathematicians (1956), in which he was awarded with the A.R. Beruni State Prize (1973) and the honorary title of "Honored Scientist of the Republic of Uzbekistan" (1970), as well as the election of honorary doctors of a number of foreign universities.

For his great achievements in the development of mathematics and training of scientific personnel, as well as for his effective social activity, S.Kh. Sirojiddinov was awarded with the highest state awards - many medals. In 2002 (posthumously) he was awarded with the Medal of Merit.

Uzbek mathematicians remember our teacher S.Kh. Sirojiddinov with deep gratitude and pride. We believe that his life and work in the development of mathematics in Uzbekistan will serve as a model for future young mathematicians.

Academician Sh.Q.Formanov,

National University of Uzbekistan

Head of " Theory of Probability and Mathematical Statistics" department,

Doctor of physics and mathematics sciences O.Sh.Sharipov,

Institute of Mathematics named after VI Romanovsky of the Academy of Sciences of Uzbekistan

Head of the Laboratory of Stochastic Analysis department,

Doctor of physics and mathematics sciences Ya.M.Khusanboev.

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