20E15 10 20F50 6 20F19 5 20F22 5 20E34 4 soluble group 4 abnormal subgroups 3 locally nilpotent residual 3 pronormal subgroups 3 radical group 3 20F14 2 20F16 2 20F18 2 arrangement of subgroups 2 fan subgroups 2 finite special rank 2 locally finite group 2 locally nilpotent radical 2 normal subgroups 2 periodic group 2 pronormal subgroup 2 self-normalizing subgroup 2 subnormal subgroup 2 transitively normal subgroups 2 06C99 1 16S90 1 20-00 1 2019 1 20B07 1 20C07 1