Torsors of Generalized del Pezzo Tori and Brauer Groups

Abstract: Using cohomological Mackey functors, we give an explicit Brauer group classification of torsors under tori of generalized del Pezzo varieties. This identifies the image of Lamarche's Brauer invariants and extends the Brauer-theoretic description in Blunk's classification of degree-six del Pezzo surfaces. We also determine which finite field extensions can appear in other Brauer group presentations of these torsors. The same tori act on Losev-Manin spaces, so the computation applies to these toric varieties as well.