ABSTRACT
A critical assumption of the hot big bang model of the universe is that matter is homogeneously distributed in space over a certain scale. It is usually assumed that under this condition the Friedmann-Robertson-Walker (FRW) metric correctly describes the dynamics of the universe. Investigating this assumption is then of fundamental importance in cosmology and much current research is devoted to this issue. In this chapter, we will review the current debate on the spatial properties of galaxy distribution.
