| Affiliation: | 1. Department of Natural and Mathematical Sciences, Turin Polytechnic University in Tashkent, Niyazov Str. 17, 100095 Tashkent, Uzbekistan;2. Dipartimento di Scienze Matematiche, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy;3. Dipartimento di Matematica e Informatica, Università degli Studi di Parma, Parco Area delle Scienze 53/A, I-43124 Parma, Italy;1. Facultad de Ciencias, Universidad Nacional San Luis Gonzaga-UNICA, Ica, Peru;2. Departamento de Matemática, Universidad del Bío-Bío, Concepción, Chile;3. Departamento de Matemática, Universidade Federal de Pernambuco - UFPE, Recife, PE, Brazil;1. Department of Mathematics, Chosun University, Kwangju 501-759, Republic of Korea;2. Department of Mathematics, Chonnam National University, Kwangju 501-757, Republic of Korea;3. National Institute for Mathematical Sciences, Daejeon 305-811, Republic of Korea |
