Soltani Nor El Houda2022-12-052022-12-052021-06-10https://dspace.univ-annaba.dz//handle/123456789/740The work presented in this thesis is devoted to studying the existence and multiplicity of non-trivial positive solutions of a singular fractional elliptic type system associated with the fractional p-Laplacian operator in a bounded domain R N . The results are obtained using some of the variational techniques, Nehari Manifold, Fibering method (F.M), and applying the Ekeland variational principle.enETUDE D’EXISTENCE ET NON EXISTENCES DE SOLUTIONS DE CERTAINES CLASSES D’EQUATIONS ET DES SYSTEMES ELLIPTIQUES SEMI-LINEAIRES