  By studying the color structure of multi-particle production processes in
p+A-type (dilute-dense) collisions, we find that higher-point functions beyond
typical dipoles and quadrupoles, e.g., sextupoles, octupoles, etc., naturally
appear in the cross sections, but are explicitly suppressed in the large-N_c
limit. We evaluate the sextupole in the McLerran-Venugopalan model and find
that, in general, its analytical form cannot be written as combination of
dipoles and quadrupoles. Within the Color Glass Condensate framework, we
present a proof that in the large-N_c limit, all multi-particle production
processes in the collision of a dilute system off a dense can, up to all orders
in \alpha_s, be described in terms of only dipoles and quadrupoles.
