Kharkiv school of M. I. Kadets and mathematics of Tula

The authors of the article set themselves the tasks: to tell about the unexpected and long cooperation and interaction of teachers and scientists of the Tolstoy Tula State Pedagogical University and the Mikhail Iosifovich Kadets Kharkiv School, as well as about some scientific works of the Kharkiv mathematicians of the Mikhail Iosifovich Kadets School and mathematicians of the city of Tula in the twenty-year period 1986-2006. he role of V. I. Rybakov is particularly noted. Under his leadership, a Tula student conducted scientific work, who later, after studying at the Mikhail Iosifovich Kadets Kharkiv School, became a candidate of physical and mathematical sciences. Vladislav Ivanovich Rybakov obtained deep, meaningful scientific results. For example, you can read about "the classical theory of Rybakov" in books and articles published in the international mathematical press. Mikhail Iosifovich Kadets was interested in Vladislav Ivanovich's scientific activity. The Kharkiv school of Kadets at that time became world famous. Not only scientific work, Mikhail Iosifovich paid a lot of attention and effort to pedagogical work. Nineteen of his students, including Rybakov's student, defended their PhD theses, seven of them became doctors of science. M. I. Kadets generously shared his mathematical ideas with his students. The article presents some results obtained by Kharkiv mathematicians of the Kadets school and Tula mathematicians close to them in scientific interests in the period 1986-2006.