The Impact of Emigration on Slovak Mathematics: The Case of the Bratislava Graph Theory Seminar

Appendix: Brief Profiles of the Founders of the Bratislava Graph Theory Seminar

Professor RNDr Anton Kotzig, DrSc (Figure 1), was born on October 22, 1919, in the village of Kočovce, Slovakia, and died on April 20, 1991, in Montreal, Canada. He attended Charles University in Prague. Due to the German annexation of Czechia and Moravia between 1939 and 1945, he did not complete his studies in Prague and returned to Slovakia, where he continued his studies at Comenius University in Bratislava and in 1943 was awarded the title RNDr (rerum naturalium doctor, the Slovak equivalent of a master of science) for his work in statistics. From 1940 to 1948 he worked as a statistician for the Central Bureau of the Social Insurance Department of Mathematics and Statistics, serving as the leader of that department from 1942 to 1948. Between 1951 and 1959 he was a professor at the University of Economics in Bratislava, where he served between 1952 and 1958 as the university’s rector. Between 1959 and 1964 he was the first director of the Institute of Mathematics in Bratislava, the birthplace of the Bratislava graph theory seminar. From 1965 to 1969 he served as the head of the Department of Applied Mathematics at the Faculty of Natural Sciences of Comenius University, and he was the dean of that school for a year, from 1965 to 1966. In 1961, he was awarded the DrSc degree (doctor of science, the highest scientific degree awarded at that time in Slovakia) at Charles University, in Prague.

He is well known for the Ringel–Kotzig conjecture on graceful labeling of trees and Kotzig’s theorem on the degrees of vertices in convex polyhedra. In 1999, a commemorative plaque was unveiled at his birthplace in Kočovce on the occasion of the eightieth anniversary of his birth [1].

Figure 1

Anton Kotzig (photograph courtesy of the Department of Algebra and Geometry, Comenius University).

RNDr Juraj Bosák, DrSc (Figure 2), was born on April 6, 1933, in Bratislava, and died there on April 5, 1987. From 1954 he worked at Comenius University, where he was viewed by his students as a very good teacher, but was later found politically unreliable by the authorities, and in 1959 he had to move to the Department of Mathematics of the Slovak Academy of Sciences,⁶ where he did not have direct daily contact with students. He worked for several years in the field of semigroups, and switched to graph theory in 1961. In 1963, he was one of the organizers of the graph theory conference in Smolenice mentioned above. He wrote a successful monograph, Decompositions of Graphs [3], to which he planned to write a sequel, but his preparations were interrupted by illness. He is the author of almost 30 mathematical articles on graph theory as well as two books. His hobbies included compositional chess, and he played a significant role in the preparation of Slovak chess terminology [29].

Figure 2

Juraj Bosák (photograph courtesy of Juraj Bosák’s family).

Professor RNDr Alexander Rosa, PhD (Figure 3), was born on January 26, 1937, in Bratislava. He was Kotzig’s graduate student. He is considered one of the most important Slovak mathematicians, particularly in the areas of design theory and graph theory. He began his scientific work at the Slovak Academy of Sciences in the 1960s. In 1968, he emigrated to Canada, where he is professor emeritus at McMaster University. He still collaborates with many Slovak mathematicians and has written more than 200 mathematical articles and six books. He is one of the founders of the Institute of Combinatorics and Applications as well as of the influential Journal of Combinatorial Designs, where he served for fifteen years as one of its three editors.

Figure 3

Alex Rosa (photograph courtesy of Alex Rosa).

Professor RNDr Štefan Znám, DrSc (Figure 4), was born on February 9, 1936, in the village of Vel’ký Blh, and passed away on July 17, 1993, in Bratislava. Štefan Znám began his scientific career working in number theory, but later became interested in graph theory as well. He published over 52 mathematical articles and proved several well-known hypotheses. For example, he substantially improved some previous estimates of Erdős, Rényi, and Vera Sós. In particular, he contributed significantly to the area of extremal graph theory. He prepared several television scripts aimed at popularizing mathematics, and his contributions to this popularization included about 20 articles. He wrote five books and a number of university texts [28]. He was the dissertation adviser of a number of graph theorists who are now among the leading members of the Slovak graph theory community. A plaque devoted to his memory was unveiled at his birthplace in Vel’ký Blh in 2019.

Figure 4

Štefan Znám (photograph courtesy of Alex Rosa).