Affiliation: | 1. Faculty of Mathematics, “Al.I. Cuza” University of Iaşi and “Octav Mayer” Institute of Mathematics, Iaşi, Romania;2. University of Milan, Department of Mathematics, Milan, Italy;3. University of Guelph, Department of Mathematics and Statistics, Guelph, Ontario, Canada;4. Khalifa University, Department of Applied Mathematics and Sciences, Abu Dhabi, United Arab Emirates;5. University of Milan, Department of Economics, Management, and Quantitative Methods, Milan, Italy |