Li Feng
[
School of Mathematical Science and Computing Technology, Central South University, Changsha 410075, Hunan, PR China
]
Liu Yirong
[
School of Mathematical Science and Computing Technology, Central South University, Changsha 410075, Hunan, PR China
]
Li Hongwei
[
School of Mathematics, Linyi University, Linyi 276005, Shandong, PR China
]