ABSTRACT
The schemes associated with the Relative Building are examples of Building type schemes. An Incidence type scheme is a subscheme of a finite product of Building type schemes defined in terms of the Incidence scheme. The incidence relation in buildings plays a very important role in the description of their associated geometry. In the schematic setting the graph of the incidence relation appears as a subscheme of the galleries configurations that are introduced are sections of fiber products of the Incidence scheme with itself. One may say that the types of relative position between couples of parabolics are generated by the "types of incidence" between couples of parabolics. Schubert cells are obtained as fiber products of cells defined in terms of the incidence relation, along galleries of types of relative position. These decompositions give rise to smooth resolutions of their schematic closures.
