Sergey Mergelyan was an outstanding mathematician, a member-correspondent of the USSR Academy of Sciences, and a full member of the Academy of Sciences of the Armenian SSR and the Republic of Armenia. He also was a laureate of the Order of the Red Banner of Labor, the Stalin Prize, and holder of the Order of St. Mesrop Mashtots.
Mergelyan was the youngest doctor of science in the history of the USSR – a doctoral degree was awarded to him at the age of 20 years.
The surname “Mergelov” given to him at birth was changed to “Mergelyan” due to patriotic considerations by the mathematician himself before his trip to Moscow.
Mergelyan graduated from the Yerevan State University in 1947. He has worked in the university from 1945 to 1957. In 1954-1958 and 1964-1968, he worked at the Moscow State University. In 1956–1960, he was the director of the Scientific Research Institute of Mathematical Machines and the Computing Center of the Academy of Sciences of the Armenian SSR.
In 1961–1971, Mergelyan worked at the Mathematical Institute of the Academy of Sciences of the USSR. Since 1971, he has served as vice-president of the Academy of Sciences of the Armenian SSR. He also was a member of the Supreme Council of the Armenian SSR of the 5th and 8th convocations.
In the early 1950s, Mergelyan founded the Scientific Research Institute of Mathematical Machines and a computer center in Yerevan, heading them since 1956. In the 1960s-1970s, he founded and headed the department of complex analysis of the Steklov Institute of Mathematics, at the same time being the deputy academician-secretary of the Department of Mathematics of the USSR Academy of Sciences. In 1982-1986, he was the rector of the Kirovakan Pedagogical Institute.
The main works of Mergelyan include the theorem of functions of a complex variable, the theory of approximation, and theories of potential and harmonic functions. In 1951, he solved the problem of the approximation of continuous functions by polynomials. Several years later, he solved the Bernstein Approximation Problem.
Sergey Mergelyan passed away in 2008 at the age of 80. At his request, his ashes were buried at the Novodevichy Cemetery in Moscow next to his wife and mother.