  We give a natural notion of nondegeneracy for singular points of integrable
non-Hamiltonian systems, and show that such nondegenerate singularities are
locally geometrically linearizable and deformation rigid in the analytic case.
We conjecture that the same result also holds in the smooth case, and prove
this conjecture for systems of type $(n,0)$, i.e. $n$ commuting smooth vector
fields on a $n$-manifold.
