Maldeghem, Epimorphisms of generalized polygons, Part 2: Some existence and non-existence results

A generalized polygon is a thick incidence geometry of rank 2 such that the girth of the incidence graph is twice the diameter of the incidence graph. These geometries are intro-duced by Tits [17] for group-theoretical purposes, but became an interesting research object in their own right. For an overview of the geometric study, see [19]