Affiliation: | 1. Department of Mathematics, University of Denver, 2390 S. York St., Denver, USA;2. Czech Technical University in Prague, Faculty of Electrical Engineering, Technická 2, 166 27 Prague 6, Czech Republic;1. Tulane University, Department of Mathematics, 6823 St. Charles Ave., New Orleans, LA 70118, USA;2. Department of Mathematics, University of Nebraska – Lincoln, Lincoln, NE 68588, USA;3. University of Education, Hue University, 34 Le Loi St., Hue, Viet Nam;1. Universidad de Cádiz, Puerto Real, Cádiz, Spain;2. CMCC, Universidade Federal do ABC, Santo André, Brazil;3. CMUP, Faculdade de Ciências, Universidade do Porto, Porto, Portugal;4. Moscow Center for Fundamental and Applied Mathematics, Moscow, Russia;5. Departamento de Matemática, Universidade Federal de Santa Catarina, Florianópolis, Brazil;6. Departamento de Matemática, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal;7. Saint Petersburg University, Saint Petersburg, Russia;1. Utah State University, Department of Mathematics and Statistics, Logan UT 84341, USA;2. Hung Vuong University, Faculty of Natural Sciences, Viet Tri, Phu Tho, Viet Nam;3. Université Bretagne Sud, Laboratoire de Mathématiques de Bretagne Atlantique, UMR CNRS 6205, Campus de Tohannic, BP 573 F-56017 Vannes, France |