Sharkovsky, Oleksander [Шарковський, Олександер; Šarkovs'kyj], b 7 December 1936 in Kyiv. Mathematician; corresponding member of the Academy of Sciences of the Ukrainian SSR (now National Academy of Sciences of Ukraine) since 1978. A graduate of Kyiv University (1958), he has worked at the Institute of Mathematics of the Academy of Sciences of the Ukrainian SSR since 1961 and at Kyiv University since 1967. His main publications deal with the theory of dynamical systems, theories of stability and oscillations, and the development of qualitative and analytical methods in the theory of functional and functional-differential equations (and the same equations with delay). He developed a celebrated theorem on continuous functions in 1964, which attracted attention in the mid-1970s after a new and surprising theorem proven by S. Lie and J. Yorke was shown to be a special case of Sharkovsky’s general scheme. He has also made contributions to difference equations and their application.
[This article originally appeared in the Encyclopedia of Ukraine, vol. 4 (1993).]