English

Ramified extensions of degree $p$ and their {H}opf-{G}alois module structure

Number Theory 2015-11-18 v1

Abstract

Cyclic, ramified extensions L/KL/K of degree pp of local fields with residue characteristic pp are fairly well understood. Unless \mboxchar(K)=0\mbox{char}(K)=0 and L=K(πKp)L=K(\sqrt[p]{\pi_K}) for some prime element πKK\pi_K\in K, they are defined by an Artin-Schreier equation. Additionally, through the work of Ferton, Aiba, de Smit and Thomas, and others, much is known about their Galois module structure of ideals, the structure of each ideal PLn\mathfrak{P}_L^n as a module over its associated order AK[G](n)={xK[G]:xPLnPLn}\mathfrak{A}_{K[G]}(n)=\{x\in K[G]:x\mathfrak{P}_L^n\subseteq \mathfrak{P}_L^n\} where G=\mboxGal(L/K)G=\mbox{Gal}(L/K). This paper extends these results to separable, ramified extensions of degree pp that are not Galois.

Keywords

Cite

@article{arxiv.1511.05503,
  title  = {Ramified extensions of degree $p$ and their {H}opf-{G}alois module structure},
  author = {G. Griffith Elder},
  journal= {arXiv preprint arXiv:1511.05503},
  year   = {2015}
}