Aleksandr Mikhaylovich Lyapunov (May 25 / June 6, 1857, Yaroslavl — November 3, 1918, Odessa) was a Russian mathematician and mechanician, a full member of the Saint Petersburg Academy of Sciences, and the creator of the modern theory of the stability of motion of mechanical systems. He attended the gymnasium in Nizhny Novgorod, where he spent his youth.

Origins and Education

He was born into the family of the astronomer Mikhail Vasilyevich Lyapunov, who at the time headed the Demidov Lyceum in Yaroslavl. After his father's death in 1868, the family — his mother and three sons, Aleksandr, Sergey (the future composer), and Boris (the future linguist) — moved to Nizhny Novgorod. In 1864–1870 Aleksandr also lived in villages of the Simbirsk Governorate — Pletnikha, Bolobonovo, and Teply Stan (now the selo of Sechenovo in Nizhny Novgorod Region) — with his relatives the Sechenovs: his education was overseen by Rafail Sechenov, who at the same time taught his own daughter Natalya, who later became the scholar's wife.

The Nizhny Novgorod Years

In 1870 Aleksandr entered the third grade of the Nizhny Novgorod Boys' Gymnasium, where he immediately showed an aptitude for the exact sciences. In 1876 he graduated from the gymnasium with a gold medal and entered Saint Petersburg University — at first in the natural sciences division of the Faculty of Physics and Mathematics, but a month later he transferred to the mathematics division. A memorial plaque in the scholar's honor has been installed on the building of the former Nizhny Novgorod Boys' Gymnasium (now the main building of Minin University, 1 Ulyanova Street).

Scientific Career

At Saint Petersburg University, Lyapunov attended lectures by Mendeleev and became a student of Pafnuty Chebyshev. He graduated from the university with a gold medal in 1880. In 1881 he published his first works on hydrostatics; in 1885 he defended his master's dissertation, "On the Stability of Ellipsoidal Forms of Equilibrium of a Rotating Fluid" — a topic suggested by Chebyshev — and took over the Chair of Mechanics at Kharkov University. At the same time he taught theoretical mechanics at the Kharkov Technological Institute and took an active part in the Kharkov Mathematical Society, becoming its chairman in 1899.

His doctoral dissertation, "The General Problem of the Stability of Motion," defended on September 30, 1892, at Moscow University, brought Lyapunov worldwide recognition: in it he developed a mathematical apparatus for describing the behavior of mechanical systems with a finite number of parameters under the influence of perturbations. The results of this work became the foundation of automatic control theory, including flight control systems for aircraft and rockets. In 1900 he was elected a corresponding member, and in 1901 a full member of the Saint Petersburg Academy of Sciences in the chair of applied mathematics; from 1902 he lived in Saint Petersburg and devoted himself entirely to scientific work. He was also a corresponding member of the Paris Academy of Sciences and a member of the National Academy of the Lincei (Italy).

Final Years

In the summer of 1917 Lyapunov came to Odessa with his wife Natalya Rafailovna, who was suffering from tuberculosis. There he took up a chair at Novorossiysk University and managed to deliver seven two-hour lectures of the course "Foundations of the Hydrostatic Theory of the Figures of Celestial Bodies"; the last took place on October 28, 1918. On October 31 Natalya Rafailovna died. The same day Lyapunov shot himself in the head, leaving a request to be buried next to his wife. Without regaining consciousness, he died on November 3, 1918. Among the scholar's papers an unfinished manuscript in French was found, containing a proof of the existence of equilibrium figures close to ellipsoidal for a non-homogeneous fluid; the manuscript was copied and delivered to the Academy of Sciences. He is buried in Odessa at the Second Christian Cemetery.

Links

  • Wikidata (Q310788 — entry in the free knowledge base)
  • VIAF (5727493 — Virtual International Authority File)
  • ISNI (0000000108659318)
  • GND (118811428 — German National Library catalog)

Sources

  1. names52.ru — Lyapunov Aleksandr Mikhaylovich