1. Department of Mathematics and ComputerScience, ACSY Team-Laboratory of Pure and Applied Mathematics, Abdelhamid Ibn Badis UniversityMostaganem, P.O.Box 227/118, 27000 Mostaganem, Algeria
2. National HigherSchool of Mathematics, Scientific and Technology Hub of Sidi Abdellah, ACSY Team-Laboratory of Pureand Applied Mathematics(UMAB), P.O. Box 75, Algiers 16093, Algeria