Subnormal Subgroups

Abstract

Subnormality is a very natural generalisation of normality. Not much attention was given to subnormal subgroups until Wielandt proved his classic result on join of sub- normal subgroups of finite groups in 1939.[3] In my thesis, I am reviewing the properties of subnormal subgroups and those groups which have every subgroup subnormal. I have devoted the first chapter to give elementary results on join of subnormal sub- groups. In the end of the first chapter, I have given three proofs of Wielandt join theorem. In the second chapter, I have focused on those groups which have every subgroup subnormal. My main focus is to study non-nilpotent groups with every subgroup subnormal, mainly Heineken-Mohamed groups.