English

Reduction of Hyperelliptic Curves in Characteristic $\not=2$

Algebraic Geometry 2021-12-13 v1

Abstract

Let KK be the quotient field of a discrete valuation ring RR with residue characteristic 2\not=2, and let CC be a hyperelliptic curve over KK. We assume that all geometric branch points of the double covering CPK1C\twoheadrightarrow{\mathbb P}^1_K are rational and mark both CC and PK1{\mathbb P}^1_K with these branch points. After possibly replacing RR by a ramified extension of degree 22, we give a direct construction for the stable model of CC as a marked curve over RR. We deduce that the closed fiber of this stable model is determined completely by the closed fiber of the stable model of the marked PK1{\mathbb P}^1_K. In particular, the dual graph and other information for the former can be read off directly from the corresponding information for the latter.

Keywords

Cite

@article{arxiv.2112.05550,
  title  = {Reduction of Hyperelliptic Curves in Characteristic $\not=2$},
  author = {Tim Gehrunger and Richard Pink},
  journal= {arXiv preprint arXiv:2112.05550},
  year   = {2021}
}