Leontyev Alexey Fyodorovich (27 March 1917, selo of Yakovtsevo, Nizhny Novgorod Governorate — 14 April 1987, Ufa) was a Soviet mathematician, Doctor of Physical and Mathematical Sciences (1948), professor (1949), Corresponding Member of the USSR Academy of Sciences (1970), and Honored Scientist of the Bashkir ASSR (1975). A graduate and later a staff member of Lobachevsky Gorky State University, he founded a scientific school in the theory of functions of a complex variable. Leontyev's main scientific achievement is considered to be the creation of the theory of representing analytic functions by series of exponentials — he turned series of exponentials into an effective tool for approximating functions.[3][1]

Origins and education

Alexey Leontyev was born into a peasant family as the thirteenth child. His father, Fyodor Kharitonovich, died in 1927, and his mother died soon afterward; the children were raised by their older brothers and sisters. In 1929 Alexey finished the village primary school and continued his studies in Dzerzhinsk. Leontyev completed his secondary education in 1934 at a school in the city of Gorky — as Nizhny Novgorod was then called.[3] In 1939 he graduated with distinction from Gorky State University, after which he entered postgraduate study under Professor I. R. Braytsev.[1]

With the start of the Great Patriotic War in 1941, Leontyev joined the people's militia and took part in building defensive lines. In 1942 he defended his candidate's dissertation, titled "Differential-Difference Equations."[1]

Scientific and teaching career

From 1942 Leontyev taught at Gorky State University and gave lectures in mathematics at the Mari Pedagogical Institute. In 1945 he entered doctoral study at the Steklov Mathematical Institute of the USSR Academy of Sciences; his scientific adviser was Corresponding Member of the USSR Academy of Sciences A. O. Gelfond. In 1948 Leontyev defended his doctoral dissertation, "On a Class of Functions Defined by Series of Dirichlet Polynomials." The official opponents at the defense were M. V. Keldysh and M. A. Lavrentyev, who judged the dissertation outstanding.[3][1]

From 1948 to 1954 Leontyev headed the Department of Higher Mathematics at Gorky State University. Then, from 1954 to 1962, he headed the Department of Mathematics and the Department of Special Courses in Higher Mathematics at the Moscow Power Engineering Institute (MPEI). From 1962 to 1971 he worked as a senior researcher at the Steklov Institute, combining this post with teaching at MPEI. From 1971 Leontyev headed the Sector of Function Theory in the Division of Physics and Mathematics of the Bashkir Branch of the USSR Academy of Sciences, as well as a department in the Faculty of Mathematics of Bashkir State University, where a mathematical school in the theory of functions of a complex variable took shape under his leadership.[1]

Leontyev was the author of more than 120 scientific works, including three monographs. His monographs include "Series of Dirichlet Polynomials and Their Generalizations" (1951), "Series of Exponentials" (1976), "Sequences of Polynomials of Exponentials" (1980), and "Generalizations of Series of Exponentials" (1983); in all, he published more than 125 scientific works.[3] He took part in preparing the "Russian-English" and "English-Russian" dictionaries of mathematical terms published under the auspices of the Steklov Institute. His students include V. V. Napalkov, V. P. Gromov, Yu. N. Frolov, and G. S. Sadykhov; 35 of his students became candidates of sciences, and eight became doctors of sciences.[1]

Awards and Legacy

Leontyev was awarded the Order of the Red Banner of Labour (1975) and the Order of the October Revolution (1987). In 1989 he was posthumously awarded the USSR State Prize for his monographs "Series of Exponentials" and "Sequences of Polynomials of Exponentials."[1]

Bashkir State University has established an A. F. Leontyev scholarship for students of the Faculty of Mathematics. Every four years, the Academy of Sciences of the Republic of Bashkortostan awards a prize named after USSR Academy of Sciences Corresponding Member A. F. Leontyev for outstanding work in mathematics.[1]

Aleksey Fyodorovich Leontyev died in Ufa at the age of 70 and was buried in Moscow at the Kuntsevo Cemetery.[1]

Sources

  1. mi.ras.ru — Leontyev completed his secondary education in 1934 at a school in the city of Gorky — the name by which Nizhny Novgorod was known at the time. (archive)
  1. museum.unn.ru — March 27, 2022 marks the 105th anniversary of the birth of Aleksey Fyodorovich Leontyev — Lobachevsky University Museum (archive)
  2. dic.academic.ru — Leontyev Aleksey Fyodorovich — what is it? Who was Leontyev Aleksey Fyodorovich?