  We study the computation of local approximations of invariant manifolds of
parabolic fixed points and parabolic periodic orbits of periodic vector fields.
If the dimension of these manifolds is two or greater, in general, it is not
possible to obtain polynomial approximations. Here we develop an algorithm to
obtain them as sums of homogeneous functions by solving suitable cohomological
equations. We deal with both the differentiable and analytic cases. We also
study the dependence on parameters. In the companion paper, Invariant manifolds
of parabolic fixed points (I), these approximations are used to obtain the
existence of true invariant manifolds close by. Examples are provided.
