Let g
(resp. g′) be a Lie algebra of dimension
d≤ 3 (resp. of finite dimension)
over a field k of
characteristic ≠2. We prove that g is isomorphic to g′ as
Lie algebras over k if and only if
the enveloping algebra U(g) of
g is isomorphic to
U(g′)
as k-algebras.