Some notes on Lie ideals in division rings
Abstract
A Lie ideal of a division ring AA is an additive subgroup LL of AA such that the Lie product [l,a]=la−al[l,a]=la−al of any two elements l∈L,a∈Al∈L,a∈A is in LL or [l,a]∈L[l,a]∈L. The main concern of this paper is to present some properties of Lie ideals of AA which may be interpreted as being dual to known properties of normal subgroups of A∗A∗. In particular, we prove that if AA is a finite-dimensional division algebra with center FF and charF≠2charF≠2, then any finitely generated ℤ-module Lie ideal of A is central. We also show that the additive commutator subgroup [A,A] of A is not a finitely generated ℤ-module. Some other results about maximal additive subgroups of A and Mn(A) are also presented.
Communicated by L. Rowen