FARDI, Nihel2023-12-112023-12-112023-06-04http//localhost:8080/jspui/handle/123456789/10961The work presented in this memory is devoted to the study of the existence and multiplicity of nontrivial solutions for a fourth-order elliptic problem (p-biharmonic). The results are obtained by using the Nehari manifold and Ekeland's variational principle.enp-biharmonic operator, Nehari manifold, Ekeland variational principleThesis