Motives of unitary and orthogonal homogeneous varieties

Abstract

Grothendieck-Chow motives of quadric hypersurfaces have provided many insights into the theory of quadratic forms. Subsequently, the landscape of motives of more general projective homogeneous varieties has begun to emerge. In particular, there have been many results which relate the motive of a one homogeneous variety to motives of other simpler or smaller ones. In this paper, we exhibit a relationship between motives of two homogeneous varieties by producing a natural rational map between them which becomes a projective bundle morphism after being resolved. This allows one to use formulas for projective bundles and blowing up to relate the motives of the two varieties. We believe that in the future this ideas could be used to discover more relationships between other types of homogeneous varieties.