English

Wild Galois representations: elliptic curves with wild cyclic reduction

Number Theory 2025-06-26 v1

Abstract

In 1990, Kraus classified all possible inertia images of the \ell-adic Galois representation attached to an elliptic curve over a non-archimedean local field. In previous work, the author computed explicitly the Galois representation of elliptic curves having non-abelian inertia image, a phenomenon which only occurs when the residue characteristic of the field of definition is 22 or 33 and the curve attains good reduction over some non-abelian ramified extension. In this work, the computation of the Galois representation in all the remaining wild cases, i.e. when the residue characteristic is p=2p=2 or 33 and the curve attains good reduction over an extension whose ramification degree is divisible by pp (without assuming the condition on the image of inertia being non-abelian), is completed. This is based on Chapter V of the author's PhD thesis.

Keywords

Cite

@article{arxiv.2506.20562,
  title  = {Wild Galois representations: elliptic curves with wild cyclic reduction},
  author = {Nirvana Coppola},
  journal= {arXiv preprint arXiv:2506.20562},
  year   = {2025}
}

Comments

Based on my PhD thesis. Comments are welcome!