Editing Aleksandr Lyapunov (section)

== Biography ==

=== Early life ===
Lyapunov was born in [[Yaroslavl]], [[Russian Empire]]. His father [[Mikhail Lyapunov|Mikhail Vasilyevich Lyapunov]] (1820–1868) was an [[astronomer]] employed by the [[Demidov Lyceum]]. His brother, [[Sergei Lyapunov]], was a gifted composer and pianist. In 1863, M. V. Lyapunov retired from his scientific career and relocated his family to his wife's estate at Bolobonov, in the Simbirsk province (now [[Ulyanovsk Oblast]]). After the death of his father in 1868, Aleksandr Lyapunov was educated by his uncle R. M. Sechenov, brother of the [[physiologist]] [[Ivan Mikhailovich Sechenov]]. At his uncle's family, Lyapunov studied with his distant cousin Natalia Rafailovna, who became his wife in 1886. In 1870, his mother moved with her sons to [[Nizhny Novgorod]], where he started the third class of the [[gymnasium (school)|gymnasium]]. He graduated from the gymnasium with distinction in 1876.{{sfn|Smirnov|1992}}

=== Education ===

In 1876, Lyapunov entered the Physico-Mathematical department at the [[Saint Petersburg State University|University of Saint Petersburg]], but after one month he transferred to the Mathematics department of the university.

Among the Saint Petersburg mathematics professors were [[Pafnuty Chebyshev|Chebyshev]] and his students [[Aleksandr Korkin|Aleksandr Nikolaevich Korkin]] and [[Yegor Ivanovich Zolotarev]]. Lyapunov wrote his first independent scientific works under the guidance of the professor of mechanics, D. K. Bobylev. In 1880 Lyapunov received a gold medal for a work on [[hydrostatics]]. This was the basis for his first published scientific works ''On the equilibrium of a heavy body in a heavy fluid contained in a vessel of a fixed form'' and ''On the potential of hydrostatic pressure''. Lyapunov also completed his university course in 1880, two years after [[Andrey Markov]] who had also graduated at Saint Petersburg University. Lyapunov maintained scientific contact with Markov throughout his life.

=== Teaching and research ===
A major theme in Lyapunov's research was the stability of a rotating fluid mass with possible astronomical application. This subject was proposed to Lyapunov by [[Pafnuty Chebyshev|Chebyshev]] as a topic for his masters thesis which he submitted in 1884 with the title ''On the stability of ellipsoidal forms of rotating fluids''. The main contribution was published in the celebrated  monograph  'A.M. Lyapunov, The general problem of the stability of motion. 1892. Kharkov Mathematical Society, Kharkov, 251p. (in Russian)'.<ref>{{cite book |last1=A.M. Lyapunov |title=The general problem of the stability of motion |date=1892 |publisher=Kharkov Mathematical Society |location=Kharkov |pages=1–251}}</ref> This led on to his 1892 doctoral thesis ''The general problem of the stability of motion''.{{sfn|Lyapunov|1892}} The thesis was defended in Moscow University on 12 September 1892, with [[Nikolay Yegorovich Zhukovsky|Nikolai Zhukovsky]] and V. B. Mlodzeevski as opponents. In 1908, the Kharkov edition was translated to French and republished by the [[University of Toulouse]]: 'Probleme General de la Stabilite du Mouvement, Par M.A. Liapounoff. Traduit du russe par M.Edouard Davaux'.
 
In 1885, Lyapunov became [[privatdozent]] and was proposed to accept the chair of mechanics at [[Kharkov University]], where he went the same year. About the initial stay at [[Kharkov]], Smirnov writes in his biography of Lyapunov:

{{quote|text=Here at first, the research activity of Lyapunov was cut short. It was necessary to work out courses and put together notes for students, which took up much time.{{sfn|Smirnov|1992}}}}

His student and collaborator, [[Vladimir Steklov (mathematician)|Vladimir Steklov]], recalled his first lecture in the following way: "A handsome young man, almost of the age of the other students, came before the audience, where there was also the old Dean, professor Levakovsky, who was respected by all students. After the Dean had left, the young man with a trembled voice started to lecture a course on the dynamics of material points, instead of a course on [[dynamical system]]s. This subject was already known to the students from the lectures of professor Delarue. But what Lyapunov taught us was new to me and I had never seen this material in any textbook. All antipathy to the course was immediately blown to dust. From that day students would show Lyapunov a special respect."{{sfn|Smirnov|1992}}

=== Later years ===
Lyapunov returned to Saint Petersburg in 1902, after being elected acting member of the Academy of Science as well as ordinary professor in the Faculty of Applied Mathematics of the university. The position had been left vacant by the death of his former teacher, [[Pafnuty Chebyshev|Chebyshev]]. Not having any teaching obligations, this allowed Lyapunov to focus on his studies and in particular he was able to bring to a conclusion the work on the problem of Chebyshev with which he started his scientific career.

In 1908, he took part to the Fourth [[International Congress of Mathematicians|International Mathematical Congress]] in Rome. He also participated in the publication of Euler's selected works: he was an editor of the volumes 18 and 19.{{sfn|Smirnov|1992}}

=== Death ===

By the end of June 1917, Lyapunov traveled with his wife to his brother's palace in [[Odessa]]. Lyapunov's wife was suffering from tuberculosis so they moved in accordance with her doctor's orders. She died on 31 October 1918. The same day, Lyapunov shot himself in the head, and three days later he died.{{sfn|Shcherbakov|1992}} By that time, he was going blind from [[cataracts]].{{sfn|Smirnov|1992}}