English

Semi-log canonical vs $F$-pure singularities

Algebraic Geometry 2015-03-17 v3 Commutative Algebra

Abstract

If XX is Frobenius split, then so is its normalization and we explore conditions which imply the converse. To do this, we recall that given an OX\mathcal{O}_X-linear map ϕ:FOXOX\phi : F_* \mathcal{O}_X \to \mathcal{O}_X, it always extends to a map ϕˉ\bar{\phi} on the normalization of XX. In this paper, we study when the surjectivity of ϕˉ\bar{\phi} implies the surjectivity of ϕ\phi. While this doesn't occur generally, we show it always happens if certain tameness conditions are satisfied for the normalization map. Our result has geometric consequences including a connection between FF-pure singularities and semi-log canonical singularities, and a more familiar version of the (FF-)inversion of adjunction formula.

Keywords

Cite

@article{arxiv.1101.1033,
  title  = {Semi-log canonical vs $F$-pure singularities},
  author = {Lance Edward Miller and Karl Schwede},
  journal= {arXiv preprint arXiv:1101.1033},
  year   = {2015}
}

Comments

Minor changes, 21 pages, to appear in the Journal of Algebra

R2 v1 2026-06-21T17:07:59.133Z