  We consider the recursion operator approach to the soliton equations related
to the generalized Zakharov-Shabat system on the algebra sl(n,C) in pole gauge
both in the general position and in the presence of reductions. We present the
recursion operators and discuss their geometric meaning as conjugate to
Nijenhuis tensors for a Poisson-Nijenhuis structure defined on the manifold of
potentials.
