dedicated to the memory of Yuriy Trokhymchuk (17.03.1928 - 18.12.2019).
Institute of Mathematics of National Academy of Sciences of Ukraine, Kyiv, Ukraine
April 22-24, 2020
Professor Yurii Yuriiovych Trokhymchuk was a Corresponding Member of National Academy of Sciences and an outstanding mathematician who worked in complex analysis and related fields. His fundamental results have become classical.
Yurii Yuriiovych Trokhymchuk was born on March 17, 1928, in Kyiv, Ukraine. His parents were the teachers of the Russian language and literature as well as Ukrainian language and literature. That is why Yurii was a well-read teenager.
After the beginning of the Second World War his family was evacuated. Therefore, in 1944, Yurii graduated from high school in Kazakhstan (station Lugova). In the same 1944, his parents were sent to work in Lviv, where Yurii became a student of the Lviv University.
In 1949, Yurii Trokhymchuk graduated from Lviv University and continued his post graduate studies in Lviv affiliate of Academy of Sciences. His scientific adviser was a well-known expert in complex analysis L.I. Volkovyskyi. In 1953, Yu.Yu. Trokhymchuk successfully defended his Ph.D. theses.
From 1953, he worked as an associate professor at the Lviv Polygraphic Institute, and during 1955 – 1960, he worked as an associate professor at the Novosibirsk Electrotechnical Institute.
At this time he actively works on the minimal criteria of analytic functions. The results of these researches made up a basis of his Doctor Sciences theses "Continuous mappings and analytic functions" that was successfully defended at the Moscow State University in 1960. These researches are reflected in the monograph (1963), which at once was republished in English, see: Trohimchuk Ju.Ju. "Continuous mappings and conditions of monogenity", Daniel Davey & Co., New York,1964.
In 1960, Yu.Yu. Trokhymchuk has come back to Kiev and began to work as a senior research fellow at the Institute of Mathematics of the Academy of Sciences of Ukraine. He worked also as a professor of the Faculty of Mechanics and Mathematics of Taras Shevchenko Kyiv University, where he gave courses of the mathematical analysis, the function theory, the complex analysis and the topology.
Yu.Yu. Trokhymchuk has shown himself as a talented organizer of science. From 1963, during twenty years, he was the organizer of summer mathematical workshops, where the achievements of contemporary mathematics were always presented, especially, in analysis, differential equations and topology.
Yu.Yu. Trokhymchuk worked as the head of laboratory and the head of department at the Institute of Mathematics of the National Academy of Sciences of Ukraine. He was a leading researcher of the Department of Complex Analysis and Potential Theory.
The Trokhimchuk's main mathematical results are related to the complete spread of Menshov's theorems about conformal mappings from the class of univalent functions onto arbitrary continuous functions. In Trokhimchuk's papers, the combination of theory of monogenity sets and theory of inner mappings in the sence of Stoilov became one of basic methods for solving of difficult problems of the function theory. Moreover, the mentioned problems were not solved within the framework of previous classic approaches. In particular, an important problem solved by Yu.Yu. Trokhimchuk is a problem on removable singularities of harmonic and analytic functions in non-classical terms, when classic methods are not suitable for solving. His fundamental results became the basis of several fruitful investigations of many mathematicians.
Yu.Yu. Trokhymchuk wrote nearly 80 mathematical papers and 3 books, he has supervised 13 Ph.D. and 3 Doctor of Sciences theses.
In 2006, Yu.Yu. Trokhymchuk has been elected as a Corresponding Member of the National Academy of Science of Ukraine. For his significant scientific achievements Yu.Yu.Trokhymchuk was awarded by Pogorelov Prize of the National Academy of Sciences of Ukraine.