[1] Department of Fundamental Mathematics, L.N. Gumilyov Eurasian National University, Astana, Kazakhstan
[2] Department of Fundamental and Applied Mathematics, Kazakhstan Branch of M.V. Lomonosov Moscow State University, Astana, Kazakhstan
[3] Institute of Mathematics and Mathematical Modeling, Almaty, Kazakhstan
[4] Department of Differential Equations, Faculty of Mechanics and Mathematics, M.V. Lomonosov Moscow State University, Moscow, Russia
[5] Institute of Mathematics with Computing Center Subdivision of the Ufa Federal Research Center of Russian Academy of Science, Ufa, Russia
[6] Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
[7] Higher School of Economics (NRU), Nizhny Novgorog, Russia