English

When is the Albanese morphism an algebraic fiber space in positive characteristic?

Algebraic Geometry 2020-07-23 v2

Abstract

In this paper, we study the Albanese morphisms in positive characteristic. We prove that the Albanese morphism of a variety with nef anti-canonical divisor is an algebraic fiber space, under the assumption that the general fiber is FF-pure. Furthermore, we consider a notion of FF-splitting for morphisms, and investigate it of the Albanese morphisms. We show that an FF-split variety has FF-split Albanese morphism, and that the FF-split Albanese morphism is an algebraic fiber space. As an application, we provide a new characterization of abelian varieties.

Keywords

Cite

@article{arxiv.1704.08652,
  title  = {When is the Albanese morphism an algebraic fiber space in positive characteristic?},
  author = {Sho Ejiri},
  journal= {arXiv preprint arXiv:1704.08652},
  year   = {2020}
}

Comments

24 pages, v2: an error in Proposition 5.11 corrected, and the proof of Lemma 4.5 corrected