English

F-thresholds of graded rings

Commutative Algebra 2015-07-21 v1 Algebraic Geometry

Abstract

The a-invariant, the F-pure threshold, and the diagonal F-threshold are three important invariants of a graded K-algebra. Hirose, Watanabe, and Yoshida have conjectured relations among these invariants for strongly F-regular rings. In this article, we prove that these relations hold only assuming that the algebra is F-pure. In addition, we present an interpretation of the a-invariant for F-pure Gorenstein graded K-algebras in terms of regular sequences that preserve F-purity. This result is in the spirit of Bertini theorems for projective varieties. Moreover, we show connections with projective dimension, Castelnuovo-Mumford regularity, and Serre's condition SkS_k. We also present analogous results and questions in characteristic zero.

Keywords

Cite

@article{arxiv.1507.05459,
  title  = {F-thresholds of graded rings},
  author = {Alessandro De Stefani and Luis Núñez-Betancourt},
  journal= {arXiv preprint arXiv:1507.05459},
  year   = {2015}
}

Comments

20 pages

R2 v1 2026-06-22T10:14:57.244Z