The Ukrainian Mathematical Society with deep sadness announces that on May 16, 2018, the famous Ukrainian mathematician Serhii Koliada passed away.
Serhiy Koliada was born on December 7, 1957 in the village of Kolyada in Poltava region. In 1972-1975 he studied at the Republican Physical and Mathematical Boarding School at the Kiev University. Shevchenko. After graduation, he entered the Faculty of Mechanics and Mathematics of the University of Kiev, which he graduated with honors in 1980. In 1987 he defended, under the guidance of academician O. Sharkovsky, phD thesis "Discrete dynamic systems with negative and zero derivatives for Schwartz" and since then he worked at the Institute of Mathematics of the NAS of Ukraine. In 2007 he defended his doctoral thesis "Topological dynamics: minimality, entropy and chaos".
Serhiy Kolyada's scientific interests belonged to the theory of dynamic systems – the section of mathematics, where the methods of topology, analysis, algebra, theory of differential equations coincide. His original ideas gave this industry new discoveries and perspectives. In particular, he developed the theory of triangular square reflections, found that the minimum reflection on a compact metric space is almost mutually unambiguous, extended the definition of topological entropy to non-autonomous dynamic systems, proved that systems with positive topological entropy are chaotic according to Lee-York and introduced into consideration a new, expanded concept of chaoticity, was one of the pioneers of a new direction – dynamic topology, that is, the study of topological spaces on their reflections by methods of dynamic systems theory. In 2011 he was awarded the State Prize of Ukraine in Science and Technology for outstanding scientific achievements.
Serhiy Koliada paid a lot of attention to the popularization of mathematics among young people. He taught at the Republican Physical and Mathematical Boarding School and at the Faculty of Mechanics and Mathematics of the University of Kiev. In 2006, on his initiative and with his active participation, the Kyiv Mathematical Society was established, of which he remained president until 2014. Under his leadership, the Kyiv Mathematical Society became an important center for popularizing the latest achievements in mathematics and active communication of Ukrainian scientists. He was also the co-chairman of the competition of the Scientific Society. Shevchenko in America and the Ukraine-USA Foundation for Young Mathematicians in Ukraine and initiated the creation of scholarships. M. Ostrogradsky 10 best students mathematicians of higher education in Kiev from the All-Ukrainian charitable organization "Fund to promote the development of mathematical science."
Sergiy Koliada's works, most of which are published in reputable international journals, have been highly appreciated by specialists from all over the world. He was a speaker at numerous international scientific conferences and the organizer of a number of them. In particular, he was one of the organizers of several special scientific semesters devoted to the theory of dynamic systems and their connections with other branches of mathematics in the Max Plank Mathematical Institute (Bonn).
The untimely death of Serhiy Koliada is certainly a grave loss for the Ukrainian mathematical community. We will miss his original scientific ideas, his deep understanding of new trends and the ability to convey them to colleagues, his principledness in all cases and situations.