Joan C. Artés is Associate Professor at the Departament de Matemàtiques, Universitat Autònoma de Barcelona in Barcelona, Spain.Jaume Llibre is Full Professor at the Departament de Matemàtiques, Universitat Autònoma de Barcelona in Barcelona, Spain.Dana Schlomiuk is Honorary Professor, former Full Professor at the Département de Mathématiques et de Statistiques, Université de Montréal in Montreal, Canada.Nicolae Vulpe is Professor, Principal Researcher at the Vladimir Andrunachievici Institute of Mathematics and Computer Science in Chisinau, Moldova.