ZAKAD, FatimaSILINI, KhadidjaBOUDAOUD, Abdelmadjid: Sypervisor2024-07-032024-07-032024-06-24https://repository.univ-msila.dz/handle/123456789/43121The aim of this work is to retrace the history of these theorems, namely the principles mentioned in this memoir, in the the field of number theory, and to show that they have numerous and varied applications, which allows them to be called principles. To better demonstrate the importance of these theorems, we include some applications of each principle.enPrinciple of well-orderingPrinciple of inductionPigeonhole lemmaPrinciple of inclusion-exclusionFermat’s TheoremWilson theoremThesis