A Note on the Robustness of Pair Separations Methods in Cosmic Topology
  The pair separations statistical methods devised to detect the topology of the universe rely on the accurate knowledge of the three-dimensional positions of the cosmic sources. The determination of these positions, however, involves inevitable observational uncertainties. The only significant (measurable) sign of a nontrivial topology in PSH's was shown to be spikes. We briefly report our results concerning the sensitivity of the topological spikes in the presence of the uncertainties in the positions of the cosmic sources, which arise from uncertainties in the values of the density parameters. 
A. Bernui, G.I. Gomero, B. Mota, M.J. Reboucas