cs-Normal Subgroups of Finite Groups

The relationship between the subgroups of a finite group G and the structure of G has been extensively studied in group theory. It is interesting to use some information on the subgroups of a finite group G to determine the structure of a group G, so from the beginning's of group theory we see that some scientists interest in this side. The normality of subgroups of a finite group plays an important role in the studying of a finite group. Recently, the concepts of cs-normal subgroups was introduced by AL-Tahat in his M. Sc. thesis as a generalization for weakly c-normal subgroups by replaced the normal condition with the subnormal condition in the definition of weakly c-normal subgroup, and used the cs- normality to determine the structure of some groups. As well as, several examples and properties of cs- normal subgroups were proved. Throughout this thesis, all groups considered are finite. The main goal of this thesis is to study some properties of weakly c-normal and cs- normal subgroups of a finite group, and to use the weakly c-normality and cs-normality of some Sylow and maximal subgroups to determine the Structure of some finite groups.