1. 1 Laboratory of Pure and Applied Mathematics, Faculty of Exact Sciences and Computer , University of Jijel , Jijel , Algeria
2. 2 Laboratory of Pure and Applied Mathematics, Faculty of Exact Sciences and Computer , University of Jijel , Jijel , Algeria
3. 3 Laboratory of Pure and Applied Mathematics, Faculty of Exact Sciences and Computer , University of Jijel , Jijel , Algeria