2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/231050Jacques Tits gave a general recipe for producing an abstract geometry from a semisimple algebraic group. This expository paper describes a uniform method for giving a concrete realization of Tits's geometry and works through several examples. We also give a criterion for recognizing the automorphism of the geometry induced by an automorphism of the group. The E6 geometry is studied in depth.The writing has been cleaned up since v1Representation Theory20G15; 14M15text