We are considering below some complex problems which arise in theoretical description of the processes developing in convective zones of rotating stars. It is common knowledge that the solutions of the starting nonlinear equations of equilibrium or motion may have singularities at the rotation axis, whose elimination in the case of equations of an even more general nature including spins was treated in quantum mechanics by invoking a numerical procedure (see, e.g., Varshalovich et al. (1988)). If spin effects are disregarded, these equations, which describe general representations of conventional and Alfven velocities as expansions in orthogonal vector spherical harmonics can be cast in an analytical form Vandakurov (1999).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html