Aleksei Aleksandrovich Naumov (Obituary)

Normal Ordering and Abnormal Nonsense

“…But there is no (multiplicative) identity operator in a Lie algebra, so this is also misleading in that context. Additionally, Ado's theorem [4][5][6] tells us that every Lie algebra has a finite-dimensional representation, and this will give a representative matrix for "I " which is certainly NOT the unit matrix. So, the right-hand side of (4) or (5) is just another element of h 1 , which we may call E. This implies that we should write the Heisenberg Lie algebra as…”