“…One can show that, in this case, H * is decomposed in a finite sum of products of elements of the algebra A T , though this decomposition by no means is unique. 7,9 Provided with such a decomposition, H * is an element of the universal enveloping algebra A T of the Lie algebra A T . To be more precise, it belongs to A T + A V , where A V is the universal enveloping algebra of the Lie algebra A V ⊂ A T .…”