2019 1 20E15 1 20E34 1 20F16; Secondary 20E25 1 20F22 1 20F50 1 Primary 20E15 1 finite special rank 1 locally nilpotent group 1 locally nilpotent radical 1 locally nilpotent residual 1 non finitely generated subgroups 1 periodic group 1 pronormal subgroup 1 radical group 1 soluble group 1 transitively normal subgroup 1 transitively normal subgroups 1