  Quantum non-linear SCHROEDINGER equation is equivalent to Lieb-Liniger model.
It has non-trivial conservation laws. Recently these conservation laws were
used for evaluation of the three-body recombination rate for interacting gas of
quantum bosons. These conservations laws were known already in 1989. Submitted
text is retyping of the preprint of Centre for Mathematical Analysis of
Australian National University CMA-R33-89. It was discussed in Leningrad Branch
of the V.A. Steklov Mathematical Institute at that time. A copy of the original
preprint can be found in the section Quantum Inverse Scattering Method of the
web-page http://insti.physics.sunysb.edu/~korepin/
