Finite and Infinite Symmetries in (2+1)-Dimensional Field Theory

These days, Franco Iachello is {\it the\/} eminent practitioner applying classical and finite groups to physics. In this he is following a tradition at Yale, established by the late Feza Gursey, and succeeding Gursey in the Gibbs chair; Gursey in turn, had Pauli as a mentor. Iachello's striking achievement has been to find an actual realization of arcane supersymmetry within mundane adjacent even-odd nuclei. Thus far this is the only {\it physical\/} use of supersymmetry, and its fans surely must be surprised at the venue. Here we describe the role of $SO(2,1)$ conformal symmetry in non-relativistic Chern--Simons theory: how it acts, how it controls the nature of solutions, how it expands to an infinite group on the manifold of static solutions thereby rendering the static problem completely integrable. Since Iachello has also used the $SO(2,1)$ group in various contexts, this essay is presented to him on the occasion of his fiftieth birthday.