Alexey Andreevich Lyapunov (Russian: Алексе́й Андре́евич Ляпуно́в; 1911–1973) was a Soviet mathematician and an early pioneer of computer science. One of the founders of cybernetics, Lyapunov was member of the Soviet Academy of Sciences and a specialist in the fields of real function theory, mathematical problems of cybernetics, set theory, programming theory, mathematical linguistics, and mathematical biology.
In 1928, Lyapunov enrolled in Moscow State University to study mathematics, and in 1932 became the student of Nikolai Luzin. Under his mentorship, Lyapunov began his research in descriptive set theory. He became world-wide known for his theorem on the range of an atomless vector-measure in finite dimensions, now called the Lyapunov Convexity Theorem.
From 1934 until the early 1950s, Lyapunov was on the staff of the Steklov Mathematical Institute. When Mstislav Keldysh organized thes Department of Applied Mathematics (now the M.V. Keldysh Institute of Applied Mathematics) he suggested Lyapunov to lead its work on programming.
In 1961, Lyapunov moved to the Institute of Mathematics of the Siberian Division of the USSR Academy of Sciences (now the Sobolev Institute of Mathematics), where he founded the department of cybernetics. At Novosibirsk State University, he founded the Department of Theoretical Cybernetics and the Laboratory of Cybernetics at the Institute of Hydrodynamics of the Siberian Division of the USSR Academy of Sciences (now the Lavrentiev Institute of Hydrodynamics) which he led until the end of his life.
In 1964, Lyapunov was elected a member of the USSR Academy of Sciences and joined the Division of Mathematics.
He was awarded the Order of Lenin. In 1996, he was awarded the Pioneer of Computer Technology Medal.