  Two important pieces of nuclear structure are many-body collective
deformations and single-particle spin-orbit splitting. The former can be
well-described microscopically by simple SU(3) irreps, but the latter mixes
SU(3) irreps, which presents a challenge for large-scale, ab initio
calculations on fast modern computers. Nonetheless, SU(3)-like phenomenology
remains even in the face of strong mixing. The robustness of band structure is
reminiscent of robust, pairing collectivity that arises from random two-body
interactions.
