Symmetric Products and Q-manifolds

An example is given of a compact absolute retract that is not a Hilbert cube manifold but whose second symmetric porduct is the Hilbert cube. A factor theorem is given for nth symmetric product of the cartesian product of any absolute neighborhood retract with the Hilbert cube. A short proof is included of the known fact that symmetric products preserve the property of being a compact Hilbert cube manifold (the theorem is proved here for all Hilbert cube manifolds).