| Affiliation: | 1. Department of Mathematics, University of Brasilia, 70910-900 Brasília DF, Brazil;2. Department of Mathematics, Federal University of Goias, 75704-020 Catalão GO, Brazil;1. College of Sciences, Shanghai Institute of Technology, 201418 Shanghai, PR China;2. Institut für Algebra und Zahlentheorie, Universität Stuttgart, 70569 Stuttgart, Germany;1. Department of Mathematics, Stanford University, Stanford, CA 94305, United States of America;2. Department of Mathematics and Statistics, SUNY, Albany, NY 12222, United States of America;1. Department of Mathematics, Illinois State University, Normal, IL 61790, USA;2. Department of Mathematics, Gettysburg College, Gettysburg, PA 17325, USA;1. Facultat d''Educació, Universitat de Barcelona, Passeig de la Vall d''Hebron 171, 08035 Barcelona, Spain;2. Department of Mathematics & Statistics, Amherst College, Amherst, MA 01002, USA;3. Departament de Matemàtiques i Informàtica, Universitat de Barcelona (UB), Gran Via de les Corts Catalanes 585, 08007 Barcelona, Spain |
