  Universal properties of spin-Hall effect in ballistic 2D electron systems are
addressed. The net spin polarization across the edge of the conductor is second
order, ~\lambda^2, in spin-orbit coupling constant independent of the form of
the boundary potential, with the contributions of normal and evanescent modes
each being ~ \sqrt{\lambda} but of opposite signs. This general result is
confirmed by the analytical solution for a hard-wall boundary, which also
yields the detailed distribution of the local spin polarization. The latter
shows fast (Friedel) oscillations with the spin-orbit coupling entering via the
period of slow beatings only. Long-wavelength contributions of evanescent and
normal modes exactly cancel each other in the spectral distribution of the
local spin density.
