  Halo Occupation Distribution (HOD) is a model giving the average number of
galaxies in a dark matter halo, function of its mass and other intrinsic
properties, like distance from halo center, luminosity and redshift of its
constituting galaxies. It is believed that these parameters could also be
related to the galaxy history of formation. We want to investigate more this
relation in order to test and better refine this model. To do that, we extract
HOD indicators from EUCLID mock catalogs for different luminosity cuts and for
redshifts ranges going from 0.1 < z < 3.0. We study and interpret the trends of
indicators function of these variations and tried to retrace galaxy formation
history following the idea that galaxy evolution is the combination rather than
the conflict of the two main proposed ideas nowadays: the older hierarchical
mass merger driven paradigm and the recent downsizing star formation driven
approach.
