Proof of a conjecture of Wiegold for nilpotent Lie algebras

Let $\mathfrak{g}$ be a nilpotent Lie algebra. By the breadth $b(x)$ of an element $x$ of $\mathfrak{g}$ we mean the number $[\mathfrak{g}:C_{\mathfrak{g}}(x)]$. Vaughan-Lee showed that if the breadth of all elements of the Lie algebra $\mathfrak{g}$ is bounded by a number $n$, then the dimension of the commutator subalgebra of the Lie algebra does not exceed $n(n+1)/2$. We show that if $\dim \mathfrak{g'} > n(n+1)/2$ for some nonnegative $n$, then the Lie algebra $\mathfrak{g}$ is generated by the elements of breadth $>n$, and thus we prove a conjecture due to Wiegold (Question 4.69 in the Kourovka Notebook) in the case of nilpotent Lie algebras. Bibliography: 4 titles.

nilpotent Lie algebras, finite -groups, breadth of an element, estimate for the size of the commutator subalgebra