English

On canonical bundle formula for fibrations of curves with arithmetic genus one

Algebraic Geometry 2026-04-08 v4

Abstract

In this paper, we develop canonical bundle formulas for fibrations of relative dimension one in characteristic p>0p>0. For such a fibration from a log pair f ⁣:(X,Δ)Sf\colon (X, \Delta) \to S, if ff is separable, we can obtain a formula similar to the one due to Witaszek \cite{Wit21}; if ff is inseparable, we treat the case when SS is of maximal Albanese dimension. As an application, we prove that for a klt pair (X,Δ)(X,\Delta) with (KX+Δ)-(K_X+\Delta) nef, if the Albanese morphism aX ⁣:XAa_X\colon X \to A is of relative dimension one, then XX is a fiber space over AA.

Keywords

Cite

@article{arxiv.2308.08927,
  title  = {On canonical bundle formula for fibrations of curves with arithmetic genus one},
  author = {Jingshan Chen and Chongning Wang and Lei Zhang},
  journal= {arXiv preprint arXiv:2308.08927},
  year   = {2026}
}