Key points are not available for this paper at this time.
The galaxy four-point correlation function is defined and estimated for the Lick and Zwicky catalogs. The results are not very precise because in both cases the function is only just detected above the noise. However, the fact that the expected scaling with survey depth is found gives reason to believe these are useful measures of the spatial four-point function for galaxy separations in the range of from about 0.5/h Mpc to about 4/h Mpc (H = 100h km/s per Mpc). The results are fairly well described by a simple generalization of the observed behavior of the three-point function. This lends further support to the continuous clustering hierarchy picture for the galaxy distribution, and more generally for the idea that there is a remarkably simple statistical pattern underlying the galaxy distribution.
Fry et al. (Sat,) studied this question.