Some notes on Lie ideals in division rings
Abstract
A Lie ideal of a division ring AA is an additive subgroup L of A such that the Lie product [l,a]=la−al of any two elements l∈L,a∈A is in L or [l,a]∈L. The main concern of this paper is to present some properties of Lie ideals of A which may be interpreted as being dual to known properties of normal subgroups of A∗. In particular, we prove that if A is a finite-dimensional division algebra with center F and charF≠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