Locally nilpotent 4-Engel groups are Fitting groups
Let G be a locally nilpotent 4-Engel group. We show that the normal closure of any element from G is nilpotent of class at most 4. When G has no element of order 2 or 5, the normal closure has class at most 3. These bounds are sharp. (C) 2003 Elsevier Inc. All rights reserved.