Gunnar Fromholdovich Kangro ( Estonian Gunnar Kangro ; November 21, 1913 , Tartu - December 25, 1975 , Tartu) - Estonian Soviet mathematician . Doctor of physico-mathematical sciences , professor (1951), corresponding member of the Academy of Sciences of the Estonian SSR (1961), Honored Scientist of the Estonian SSR (1965).
| Gunnar Kangro | |
|---|---|
| est. Gunnar kangro | |
| Date of Birth | |
| Date of death | |
| A country |  Estonia  the USSR |
| Scientific field | maths |
| Place of work | University of Tartu |
| Alma mater | University of Tartu |
| Academic degree | Doctor of Physical and Mathematical Sciences |
| Academic rank | Corresponding Member of the Academy of Sciences of the ESSR |
| Awards and prizes | Honored Scientist of the Estonian SSR |
His works are mainly devoted to the theory of summation. He taught courses in mathematical analysis , functional analysis and algebra at the University of Tartu , wrote several textbooks.
Content
Biography
Gunnar Kangro was born on November 21, 1913 in Tartu in the family of engineer Fromhold Kangro (1881–1932). After graduating from Tartu Reaalgümnaasium Tartu High School in 1931, he entered the Faculty of Mathematics and Natural Sciences of the University of Tartu , where he studied mathematics . After graduating from the university in 1935 and ending the service of the Estonian army, he was appointed junior assistant in the mathematics and mechanics laboratory of the Tallinn Technical Institute (now Tallinn Technical University ). He defended his master's thesis in 1938 under the supervision of Professor Hermann Yaakson at the University of Tartu. In 1940, he received a scholarship for doctoral studies at the University of Tartu.
In July 1941, Kangro was drafted into the Red Army . He served there until February 1942, when he was sent to the Chelyabinsk Institute for Agricultural Mechanization . At the end of 1943 he was transferred to Moscow State University , where he continued his work on his doctoral dissertation.
Kangro returned to Estonia in the autumn of 1944, and since November began teaching at the University of Tartu. In 1947-1948 he was dean of the Faculty of Physics and Mathematics. He defended his doctoral dissertation in July 1947 and became a professor in 1951. In 1952-1959 he was head of the department of geometry , and from 1959 until his death in 1975, he remained head of the department of mathematical analysis .
Research
In his doctoral dissertation, he developed a new theory of convergence , which generalized the theory of Borel summation, and applied it to the study of problems related to the convergence of complex power series . He defined new summation methods and used them to characterize the properties of the sum of power series and analytic continuation . The stellar regions of convergence of power series obtained using these new summation methods allowed him to obtain results that extend the application of Borel summation methods in function theory.
In the 1950s, he laid the foundations for a systematic consideration of the summation factors together with German mathematicians Alexander Peyerimhoff and Wolfgang Jourkat. He combined the ideas of modern functional analysis with classical analysis. Together with his student Simson Baron, he began to describe summability factors for double rows.
Considering applications to Tauber ’s orthogonal series and theorems , Kangro created the theory of summability with speed based on functional analysis, which helped him solve several problems of the theory of functions and summability. In addition, he noted the main directions for applying the new theory. This work was interrupted by his sudden death in 1975.
Teaching
After the war, Kangro had a great influence on the modernization of the teaching of mathematics at Tartu State University. His courses in algebra and mathematical analysis reflects the changes that took place in these areas in the first half of the 20th century: the functional theory of polynomials was replaced by abstract algebra , mathematical analysis was based on axiomatic methods and set theory . His course in functional analysis was the starting point for a new line of research in numerical methods in Tartu.
Kandro's main contribution was to educate a new generation of mathematicians. Under his leadership, 23 master's theses in mathematics were defended. In addition to mathematical analysis, he also contributed to the development of algebra, numerical methods and geometry in Estonia. Noteworthy is his initiative to reorganize higher mathematical education at the University of Tartu in the 1960s due to the increased need for computer specialists.
Books
- 1948 Kõrgem algebra I, Teaduslik kirjastus, Tartu
- 1950 Kõrgem algebra II, Eesti Riiklik Kirjastus, Tallinn-Tartu
- 1962 Kõrgem algebra, Eesti Riiklik Kirjastus, Tallinn
- 1965 Matemaatiline analüüs I, Eesti Raamat, Tallinn
- 1968 Matemaatiline analüüs II, Valgus, Tallinn
Publications
- Verallgemeinerte Theorie der absoluten Summierbarkeit. Tartu Ülikooli Toimetised, seeria A, 37 (1942).
- Theory of summability of sequences and series. Journal of Soviet Mathematics, 5, 1-45 (1976).
Literature
- Conference materials "Methods of algebra and functional analysis in the study of operator families" : November 24-26, 1978. Tartu State University.