**Jonas Kubilius** was a Lithuanian mathematician who worked in probability theory and number theory.

- Describing these years, Kubilius used to mention his attempts to write poetry, to make a radio apparatus, ...
- Kubilius was an outstanding pupil in mathematics and in his final year at school he sometimes helped his mathematics teacher explaining difficult concepts to his fellow students.
- Kubilius graduated from the Gymnasium in Raseiniai on 16 June and on his graduation day a Soviet tank stood in the centre of the city.
- Despite the dire situation in the country, Vilnius University was still operating and Kubilius matriculated in the Mathematics and Natural Sciences Faculty in October 1940.
- During the closure, Kubilius spent a year as a teacher of mathematics at the middle school in Erzvilkas where he himself had studied.
- After returning to Vilnius University to continue his studies, Kubilius decided to write a dissertation on number theory.
- Kubilius graduated summa cum laude in 1946.
- After graduation, Kubilius was employed as an assistant in the Department of Physics and Mathematics.
- Kubilius was awarded a Candidate's degree (equivalent to a Ph.D.) in 1951 for his thesis Geometry of Prime Numbers.
- When interviewed later in life, Kubilius always stressed the high quality of the advice he received from Linnik during his years as a research student and emphasised how Linnik had a wonderful intuition as to which problems would be challenging yet might be solved with enough effort.
- Following the award of his Candidate's Degree, Kubilius returned to Vilnius where, from 1951, he was in the Institute of Physics and Technology of the Lithuanian Academy of Sciences.
- The next step for Kubilius was to write a doctoral thesis (equivalent in level to a D.Sc. or habilitation).
- This was because Moscow had contacted the Lithuanian Communist Party which had sent a telegram to Moscow saying that Kubilius was not reliable.
- Kubilius participated in reorganizing the Institute of Physics and Technology into the Institute of Physics and Mathematics and, in 1956, became an assistant director of the Institute and the head of the Division of Mathematics.
- It was thought that Kubilius was among the followers of the latter.
- It was Linnik who advised to Kubilius to call the thesis "a contribution to probability theory".
- When Kubilius returned by train from Moscow to Vilnius he was met at the railway station by a large group of Lithuanian mathematicians who had come to celebrate his success.
- Kubilius published Probability methods in number theory as a monograph in 1959.
- Kubilius was offered the position of Rector to replace Bulovas.
- At first Kubilius was reluctant to accept since he was deeply involved with mathematical research and he did not see how he could take on the role of rector without it interfering with his research output.
- Thirdly, Kubilius felt that although some research was being undertaken at the university, it was necessary to increase this markedly and to do so would require putting the right infrastructure in place.
- Despite the work involved in his role as rector, which he undertook for 33 years, Kubilius was able to continue to undertake outstanding research on applying probability theory to the theory of numbers.
- Much new material was incorporated in this edition, in particular a completely new chapter giving Kubilius's results on the number of distinct prime divisors of an integer m.
- When Kubilius became rector, the University of Vilnius was the only university in the Soviet Union in which the language of instruction was not Russian.
- Neither did the rest of the Kubilius's speech at this celebration follow the rules of the Soviet style, since he did not mention Lenin or Marx even once.
- Kubilius received much international recognition for his achievements, in particular he was awarded honorary degrees from the universities of Greifswald, Prague, Latvia and Salzburg.

Born 27 July 1921, Fermos, Erzvilkas, Jurbarkas, Lithuania. Died 30 October 2011, Vilnius, Lithuania.

View full biography at MacTutor

Origin Lithuania

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive