Question:
k isLet $k$ be a field with char k = 0$\operatorname{char} k = 0$. L isLet $L$ be a Lie k$k$-algebra, then. Then the universal envelooe U(L)envelope $U(L)$ is a PI-algebra iff L$L$ is abelian.
Remark: PI-algebra means polynomial identity algebra, an algebra that satisfies a nonzero polynomial.
Obviously, if L$L$ is abelian, then U(L)$U(L)$ is commutative. But the reverse direction is difficult for me. I also know that this is a result in an article "Two remarks on PI-algebras, V.N.Latysev". But I can not find the article.