English

Tables of pure quintic fields

Number Theory 2018-12-09 v1

Abstract

By making use of our generalization of Barrucand and Cohn's theory of principal factorizations in pure cubic fields Q(D3)\mathbb{Q}(\sqrt[3]{D}) and their Galois closures Q(ζ3,D3)\mathbb{Q}(\zeta_3,\sqrt[3]{D}) with 3 possible types to pure quintic fields L=Q(D5)L=\mathbb{Q}(\sqrt[5]{D}) and their pure metacyclic normal fields N=Q(ζ5,D5)N=\mathbb{Q}(\zeta_5,\sqrt[5]{D}) with 13 possible types, we compile an extensive database with arithmetical invariants of the 900 pairwise non-isomorphic fields NN having normalized radicands in the range 2D<1032\le D<10^3. Our classification is based on the Galois cohomology of the unit group UNU_N, viewed as a module over the automorphism group Gal(N/K)\mathrm{Gal}(N/K) of NN over the cyclotomic field K=Q(ζ5)K=\mathbb{Q}(\zeta_5), by employing theorems of Hasse and Iwasawa on the Herbrand quotient of the unit norm index (UK:NN/K(UN))(U_K:N_{N/K}(U_N)) by the number #(PN/K/PK)\#(\mathcal{P}_{N/K} / \mathcal{P}_K) of primitive ambiguous principal ideals, which can be interpreted as principal factors of the different DN/K\mathfrak{D}_{N/K}. The precise structure of the F5\mathbb{F}_5-vector space of differential principal factors is expressed in terms of norm kernels and central orthogonal idempotents. A connection with integral representation theory is established via class number relations by Parry and Walter involving the index of subfield units (UN:U0)(U_N:U_0). The statistical distribution of the 13 principal factorization types and their refined splitting into similarity classes with representative prototypes is discussed thoroughly.

Keywords

Cite

@article{arxiv.1812.02440,
  title  = {Tables of pure quintic fields},
  author = {Daniel C. Mayer},
  journal= {arXiv preprint arXiv:1812.02440},
  year   = {2018}
}

Comments

42 pages, 4 sections, 43 tables, 1 figure

R2 v1 2026-06-23T06:33:53.342Z