1. Department of Mathematics, New Uzbekistan University, Tashkent, Uzbekistan
2. Department of Mathematics, Central Asian University, Tashkent Region, Uzbekistan
3. V.I. Romanovskiy Institute of Mathematics, Uzbekistan Academy of Sciences, Tashkent, Uzbekistan
4. Department Algebra and Functional Analysis, National University of Uzbekistan, Tashkent, Uzbekistan