Groups with restiriction on their subnormal subgroups

In this thesis work we have studied the paper written by Herman Heineken titled ? Groups with restriction on their infinite subnormal subgroups ?. In this paper H.Heineken have considered Bn-groups and IBn-groups. In the same time it is shown that infinite IBn-groups are extensions of an abelian group by a Bn-group, where the structure of the abelian normal subgroup can be restricted, furthermore infinite IBn-groups are Bn+1-groups. By using the results of De Giovanni and Franciosi for Bn-groups and IBn-groups Heineken made comparison IBn-group with Bn-groups. The important preliminary that are needed in the proofs have been gathered together. Thus researches in this area made clear more detailed and put in more easily understandable form.