Abstract

We investigate the vanishing of H^1(X,mathcal {O}_X(-D)) for a big and nef mathbb {Q}-Cartier mathbb {Z}-divisor D on a log del Pezzo pair (X,Delta ) over a perfect field of positive characteristic p.

Highlights

  • It has long been known that the (Kodaira and Kawamata–Viehweg) vanishing theorems, so fundamental to birational geometry in characteristic zero, in general fail for surfaces in positive characteristic [20]

  • In [6] the authors prove the existence of an integer p0 such that over an algebraically closed field of characteristic p > p0 every log del Pezzo surface satisfies Kawamata–Viehweg vanishing theorem

  • We show that Kodaira vanishing holds on a del Pezzo surface of bounded index I in characteristic p > p0(I ) where p0(I ) is an explicit polynomial in the index I

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Summary

Introduction

It has long been known that the (Kodaira and Kawamata–Viehweg) vanishing theorems, so fundamental to birational geometry in characteristic zero, in general fail for surfaces in positive characteristic [20]. In [6] the authors prove the existence of an integer p0 such that over an algebraically closed field of characteristic p > p0 every log del Pezzo surface satisfies Kawamata–Viehweg vanishing theorem. On a log del Pezzo surface over an algebraically closed field of characteristic p ≥ 4c + 1 we can prove that H 1(X , OX (K X + A)) = 0 for every ample Q-Cartier Weil divisor A of Cartier index ≤ c (see Remark 3.5). It follows from his work that Kodaira vanishing holds for log del Pezzo surfaces of Picard rank one over an algebraically closed field of characteristic p > 5 (see [6, Lemma 6.1]). This implies that the characteristic p > 5 in Theorem D is optimal

Preliminaries
Serre vanishing and Serre duality for Z-divisors
Frobenius techniques
Geometric construction for Weil-divisors
Bend and break
Kodaira vanishing for divisors of big volume
Kodaira vanishing in large characteristic
Full Text
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