Institution: | 1. Department of Mathematics, Middle East Technical University, Ankara, 06531, Turkey;2. Department of Mathematics, Baishev University, Aktobe, 030000, Kazakhstan;3. Department of Mathematics, Aktobe Regional State University, Aktobe, 030000, Kazakhstan;1. Department of Mathematics, Yunnan University, Kunming, Yunnan 650091, People’s Republic of China;2. School of Mathematics and Computer Science, Yunnan Nationalities University, Kunming, Yunnan 650500, People’s Republic of China;3. Department of Mathematics, Kunming University, Kunming, Yunnan 650214, People’s Republic of China |