  Multidimensional Heisenberg algebras, whose creation and annihilation
operators are the N-dimensional vectors, can be injected into simple Lie
algebras g. It is demonstrated that the spectrum of their deformations can be
investigated using chains of extended Jordanian twists applied to U(g). In the
case of U(sl(N)) (for N>5) the two-dimensional Heisenberg subalgebras have nine
deformed costructures connected by four "internal" and "external" twists
composing the commutative diagram.
