English

On the trace map between absolutely abelian number fields of equal conductor

Number Theory 2015-06-26 v2

Abstract

Let L/K be an extension of absolutely abelian number fields of equal conductor, n. The image of the ring of integers of L under the trace map from L to K is an ideal in the ring of integers in K. We compute the absolute norm of this ideal exactly for any such L/K, thereby sharpening an earlier result of Kurt Girstmair. Furthermore, we define an "adjusted trace map" that allows the proof of Leopoldt's Theorem to be reduced to the cyclotomic case.

Keywords

Cite

@article{arxiv.math/0505348,
  title  = {On the trace map between absolutely abelian number fields of equal conductor},
  author = {Henri Johnston},
  journal= {arXiv preprint arXiv:math/0505348},
  year   = {2015}
}

Comments

11 pages, 1 figure, uses xypic and amscd. Completely revised version. To appear in Acta Arithmetica

R2 v1 2026-07-22T17:19:30.097Z