Translated from the text: This issue of Chebyshevskiĭ Sbornik is dedicated to the anniversaries of two outstanding Russian mathematicians: the 80th anniversary of Professor Aleksandr V. Mikhalëv, Lomonosov Moscow State University, and the 70th anniversary of Professor Alekseĭ L. Semënov, member of the Russian Academy of Sciences and member of the Russian Academy of Education.