a) K-band luminosity functions for the foreground (blue) and the extincted (red) sample (see Fig. 4). Although it is affected by extinction, the red sample is surprisingly brighter than the foreground sample (blue), suggesting that the two populations are intrinsically different. b) Empirical cumulative distribution functions for both samples, together with upper and lower simultaneous 95% confidence curves, confirming that the two populations have statistically different luminosity functions.