Alexsandr Mikhailovich Lyapunov | Biography

Known for his advances in mathematical mechanics, Alexsandr Mikhailovich Lyapunov is credited in particular with introducing ways to determine the stability of sets of regular . He is remembered today through his highly regarded academic books and the Lyapunov function for differential equations.

Born into a family of distinguished academics and artists in Yaroslavl, Russia on June 6, 1857, Lyapunov (some sources say "Liapunov") was the son of an astronomer. He was educated at home for the first part of his boyhood and then took lessons from an uncle. In 1870, Lyapunov moved with his mother and other siblings to Nizhny, Novgorod (now Gorky), where he began attending the Gymnasium. He graduated from that school in 1876, then enrolling at St. Petersburg University as a physics and math student under .

After earning his degree at the university in 1880, Lyapunov decided to heed the encouragement of his professors and stayed on as a member of the school's Mechanics Department in preparation for a professorial career. He published his first two scientific papers a year later, both of them dealing with hydrostatics. Having achieved a master's degree in 1885, Lyapunov began teaching mechanical physics at Kharkov University as a private tutor.

In 1888 he began publishing more of his original works, and in 1892 his classic "The General Problem of the Stability of Motion" appeared. He used this as the basis for his doctoral dissertation at Moscow University later that year. In 1893, Lyapunov accepted a professorship at Kharkov University, where he taught mechanics and mathematics. There, from 1896 to 1902 he conducted research in mathematical physics, introducing methods to determine the stability of differential equation sets in 1899. He also studied from 1900 to 1901.

Lyapunov left Kharkov in 1901 when he received an appointment as an associate at the St. Petersburg Academy of Sciences. At this point he devoted himself exclusively to scientific work, concentrating mainly on the theory of figures of equilibrium of heavy rotating liquids and their stability. Prior to his death, Chebyshev had challenged his student to investigate this topic, and Lyapunov spent most of the rest of his professional life on it.

In 1917 Lyapunov took his wife to Odessa for treatment of her severe tuberculosis. He took a job as a lecturer at the university there, but in 1902 his wife died of her illness, and the scientist shot himself the same day. He died three days later, on October 31, 1918.