  Frustration of magnetic systems which is caused by competing interactions is
the driving force of several unusual phenomena such as plateaus and jumps of
the magnetization curve as well as of unusual energy spectra with for instance
many singlet levels below the first triplet state. The antiferromagnetic
cuboctahedron can serve as a paradigmatic example of certain frustrated
antiferromagnets. In addition it has the advantage that its complete energy
spectrum can be obtained up to individual spin quantum numbers of s=3/2
(16,777,216 states).
