English

Higher direct images of dualizing sheaves III

Algebraic Geometry 2025-09-03 v2

Abstract

We show that for flat morphisms between varieties with rational singularities, the higher direct images of the structure sheaf are locally free. As a consequence, the identity component of the relative Picard scheme is a smooth algebraic group scheme. v.2. Bhatt pointed out that Lemma 9 was incorrect; it is now replaced. The main theorem is unchanged.

Keywords

Cite

@article{arxiv.2508.16507,
  title  = {Higher direct images of dualizing sheaves III},
  author = {János Kollár and Sándor J. Kovács},
  journal= {arXiv preprint arXiv:2508.16507},
  year   = {2025}
}