A hole in the sky - The dependence of the galaxy luminosity function on   the environment
  We have developed a method to calculate overdensities in multicolour surveys, and compare the local density contrast measured in galaxy samples with different redshift error distributions. We calculated overdensities for three COMBO-17 fields, and identified a region in the CDFS, where the density is lower by a factor of 2 compared to the other two fields. This is mainly due to a deficiency of faint red galaxies. This result is in agreement with local observations in the 2dF. 
S. Phleps, C. Wolf, J.A. Peacock, K. Meisenheimer, and E. van Kampen