English

An obstruction to the local lifting problem

Algebraic Geometry 2025-05-23 v4 Number Theory

Abstract

We are investigating the lifting problem for local actions involving semidirect products of a cyclic pp-group with a cyclic group prime to pp, where pp represents the characteristic of the special fiber. We establish a criterion based on the Harbater-Katz-Gabber compactification of local actions, enabling us to determine whether a given local action can be lifted or not. Specifically, in the case of the dihedral group, we present an example of a local dihedral action that cannot be lifted. This instance provides a more potent obstruction than the KGB obstruction.

Keywords

Cite

@article{arxiv.2304.08377,
  title  = {An obstruction to the local lifting problem},
  author = {Aristides Kontogeorgis and Alexios Terezakis},
  journal= {arXiv preprint arXiv:2304.08377},
  year   = {2025}
}

Comments

17 pages

R2 v1 2026-06-28T10:08:33.452Z