English

Fiercely ramified cyclic extensions of p-adic fields with imperfect residue field

Number Theory 2012-12-11 v2 Algebraic Geometry

Abstract

We study the ramification of fierce cyclic Galois extensions of a local field KK of characteristic zero with a one-dimensional residue field of characteristic p>0p>0. Using Kato's theory of the refined Swan conductor, we associate to such an extension a ramification datum, consisting of a sequence of pairs (δi,ωi)(\delta_i,\omega_i), where δi\delta_i is a positive rational number and ωi\omega_i a differential form on the residue field of KK. Our main result gives necessary and sufficient conditions on such sequences to occur as a ramification datum of a fierce cyclic extension of KK.

Keywords

Cite

@article{arxiv.1104.3785,
  title  = {Fiercely ramified cyclic extensions of p-adic fields with imperfect residue field},
  author = {Stefan Wewers},
  journal= {arXiv preprint arXiv:1104.3785},
  year   = {2012}
}

Comments

27 pages, revised version. Among other things, the referee has pointed out that Lemma 7.1 was incorrect. This has been corrected in the new version