Constantin Udriste, PhD, is Professor Emeritus of Mathematics-Informatics at the University Politehnica of Bucharest, Romania. He received his PhD in Mathematics from the University Babes-Bolyai of Cluj-Napoca, Romania.Ionel Tevy, PhD, is a Professor of Mathematics at the University Politehnica of Bucharest, Romania. He received his PhD in Mathematical Sciences from the Faculty of Mathematics and Mechanics of the University of Bucharest, Romania.