  The reductions of the integrable N-wave type equations solvable by the
inverse scattering method with the generalized Zakharov-Shabat systems L and
related to some simple Lie algebra g are analyzed. The Zakharov- Shabat
dressing method is extended to the case when g is an orthogonal algebra.
Several types of one soliton solutions of the corresponding N- wave equations
and their reductions are studied. We show that to each soliton solution one can
relate a (semi-)simple subalgebra of g. We illustrate our results by 4-wave
equations related to so(5) which find applications in Stockes-anti-Stockes wave
generation.
