A geometric construction of panel-regular lattices in buildings of types ~A_2 and ~C_2.

Authors: Jan Essert
Subjects: Group Theory
link: http://arxiv.org/abs/0908.2713
Abstract

Using Singer polygons, we construct locally finite affine buildings of types
~A_2 and ~C_2 which admit uniform lattices acting regularly on panels. This
construction produces very explicit descriptions of these buildings as well as
very short presentations of the lattices. All but one of the ~C_2-buildings are
necessarily exotic. Integral and rational group homology for the lattices is
also calculated.