strongly declining nature of the bright end of the luminosity function requires having very large samples to obtain significant numbers of high luminosity galaxies. Due to this, these studies were mostly inconclusive when it came to answer the question of whether BCGs were statistical or special in nature, although many works hinted at the latter. More recently, the advent of large scale surveys such as the 2dF Galaxy Redshift Survey or the Sloan Digital Sky Survey (SDSS), has motivated plentiful, ongoing work on this subject (e.g., @lms [@lm; @ls; @bernardi; @linden]).

This issue is in large part motivated by the fact that, observationally, BCGs do look different from other galaxies. They usually sit at the centre of the cluster, and tend to be considerably brighter than the remaining cluster members. The most striking case is cD galaxies, found in the centre of rich clusters and which dominate their satellites in both size and brightness, while having a characteristically distinct morphology and surface brightness distribution (e.g., @cdreview). Likewise, cD galaxies tend to be brighter than what would be expected from the bright end of the cluster galaxy luminosity function. In fact, it has been observed that, when analyzing composite luminosity functions 