V. I. Korzyuk
Institute of Mathematics of the National Academy of Sciences of Belarus; Belarusian State University
Belarus

Korzyuk Viktor I. – Academician, Professor, D. Sc. (Phy- sics and Mathematics).

11, Surganov Str., 220072, Minsk

J. V. Rudzko
Institute of Mathematics of the National Academy of Sciences of Belarus
Belarus

Rudzko Jan V. – Master (Mathematics and Computer Sciences), Postgraduate student.

11, Surganov Str., 220072, Minsk

V. V. Kolyachko
Institute of Mathematics of the National Academy of Sciences of Belarus
Belarus

Kolyachko Vladislav V. – Research Intern.

11, Surganov Str., 220072, Minsk