Kazhdan–Margulis theorem

The Kazhdan–Margulis theorem is a result in the field of geometry and group theory, specifically concerning the behavior of discrete groups of isometries in the context of hyperbolic geometry. It was formulated by mathematicians David Kazhdan and Gregory Margulis in the 1970s. The theorem primarily addresses the structure of lattices in semi-simple Lie groups, particularly focusing on the behavior of certain types of actions of these groups on homogeneous spaces.