Feninekh, KawtherDob, Sara2025-11-252025-11-252025http://dspace.univ-skikda.dz:4000/handle/123456789/5490In thispaper,weinvestigatetheexistenceofweaksolutionsforvarioustypesoffractionaldif- ferentialproblems.Thestudybeginsbyapplyingfixedpointtheorytoestablishtheexistence and uniquenessofsolutionfornonlinearfractionalellipticproblem.Then,westudythenon- linear fractionalellipticsystem.Inthefinalpart,wepresentnonlinearellipticsysteminboth resonance andnon-resonancecases,employingtheLeray–Schaudertopologicaldegreetheory to provetheexistenceofsolutionsforsuchsystemenOn the resolution of nonlinear fractional elliptic problemsAFAThesis