1. Department of General and Exact Subjects, Tashkent State University of Economics, Tashkent 100006, Uzbekistan
2. Faculty of Mathematics, University of Vienna, Oskar-Morgnstern Platz 1, 1090 Wien, Austria
3. Faculty of Physics-Mathematics, Andijan State University, Andijon 170100, Uzbekistan
4. Department of Law, Economics and Umane Sciences & Decisions_lab, University Mediterranea of Reggio Calabria, 89125 Reggio Calabria, Italy