discrete subgroup reals '''r''' standard metric topology rational numbers '''q''' '''lattice''' locally compact topological group discrete subgroup property quotient space finite invariant measure special case subgroups '''r''' sup ''n'' sup amounts usual geometric notion lattice algebraic structure lattices geometry totality lattices relatively well understood deep results borel harish chandra mostow tamagawa raghunathan margulis zimmer obtained provided examples
Formal science Mathematics Pure mathematics Geometry Discrete geometry