D-affinity and Rational Varieties
arXiv:1811.08612
Abstract
We investigate geometry of D-affine varieties. Our main result is that a D-affine rational projective surface over an algebraically closed field is a generalised flag variety of a reductive group.
Version 2: several mistakes in v.1 corrected, the main result slightly weakened. Version 3: two gaps in the proofs are filled, the section on Lefschetz Principle is replaced by a direct argument. Version 4: the results are scaled down, the previous version of the main theorem is retracted. Versions 5 and 6: minor improvements. Version 7: the final published version