English

Rationality problem for norm one tori for dihedral extensions

Algebraic Geometry 2023-11-21 v3 Number Theory Rings and Algebras

Abstract

We give a complete answer to the rationality problem (up to stable kk-equivalence) for norm one tori RK/k(1)(Gm)R^{(1)}_{K/k}(\mathbb{G}_m) of K/kK/k whose Galois closures L/kL/k are dihedral extensions with the aid of Endo and Miyata [EM75, Theorem 1.5, Theorem 2.3] and Endo [End11, Theorem 2.1]. By using a similar technique, we give refinements of the proof of stably rational cases of Endo and Miyata's theorems as an appendix of the paper.

Cite

@article{arxiv.2302.06231,
  title  = {Rationality problem for norm one tori for dihedral extensions},
  author = {Akinari Hoshi and Aiichi Yamasaki},
  journal= {arXiv preprint arXiv:2302.06231},
  year   = {2023}
}

Comments

11 pages, typos corrected, to appear in J. Algebra. arXiv admin note: text overlap with arXiv:1811.01676, arXiv:1910.01469, arXiv:1811.02145, arXiv:1210.4525, arXiv:2112.02280

R2 v1 2026-06-28T08:38:34.391Z