Affiliation: | 1. Faculty of Science and Arts, Khulais, University of jeddah, Khulais, Saudi Arabia.;2. Faculté of Sciences of Tunis, Department of Mathematics, University of Tunis El Manar, Tunis, Tunisia.;3. Faculté of Sciences of Tunis, Department of Mathematics, University of Tunis El Manar, Tunis, Tunisia. |