Rl. Hudson et Kr. Parthasarathy, CHAOS MAP FOR THE UNIVERSAL ENVELOPING ALGEBRA OF U(N), Mathematical proceedings of the Cambridge Philosophical Society, 117, 1995, pp. 21-30
It is shown that the family of representations {j(t), t is an element
of R(+)} of the universal enveloping algebra U of the N-dimensional un
itary group which is generated by the N-dimensional number process of
quantum stochastic calculus can be expressed in the form j(t) = I(t)o
psi, where psi is a bijective linear map from U onto the space L of sy
mmetric tensors over the Lie algebra, and I-t is the iterated (chaotic
) integral on L. The chaotic product is defined by the formula psi(L
M) = psi(L)psi(M) and satisfies I-t(S*T) = I-t(S)I-t(T). This work ge
neralizes and completes earlier results on the centre of U.