In the mapping from four-dimensional gauge theories to string theory i
n AdS space, many features of gauge theory can be described by branes
wrapped in different ways on S-5, RP5, or subspaces therefore. These i
nclude a baryon vertex coupling N external charges in the fundamental
representation of SU(N), a bound state of k gluons in SO(2k) gauge the
ory, strings coupled to external charges in the spinor representation
of the gauge group, and domain walls across which the low energy gauge
group changes.