  HMC histories for light dynamical overlap fermions tend to stay in a fixed
topological sector for many trajectories, so that the different sectors are not
sampled properly. Therefore the suitable summation of observables, which have
been measured in separate sectors, is a major challenge. We explore several
techniques for this issue, based on data for the chiral condensate and the
(analogue of the) pion mass in the 2-flavour Schwinger model with dynamical
overlap-hypercube fermions.
