English

Monogenic pure cubics

Number Theory 2020-09-08 v1

Abstract

Let k2k\geq 2 be a square-free integer. We prove that the number of square-free integers m[1,N]m\in [1,N] such that (k,m)=1(k,m)=1 and Q(k2m3)\mathbb{Q}(\sqrt[3]{k^2m}) is monogenic is N1/3\gg N^{1/3} and N/(logN)1/3ϵ\ll N/(\log N)^{1/3-\epsilon} for any ϵ>0\epsilon>0. Assuming ABC, the upper bound can be improved to O(N(1/3)+ϵ)O(N^{(1/3)+\epsilon}). Let FF be the finite field of order qq with (q,3)=1(q,3)=1 and let g(t)F[t]g(t)\in F[t] be non-constant square-free. We prove unconditionally the analogous result that the number of square-free h(t)F[t]h(t)\in F[t] such that deg(h)N\deg(h)\leq N, (g,h)=1(g,h)=1 and F(t,g2h3)F(t,\sqrt[3]{g^2h}) is monogenic is qN/3\gg q^{N/3} and N2qN/3\ll N^2q^{N/3}.

Keywords

Cite

@article{arxiv.2009.02442,
  title  = {Monogenic pure cubics},
  author = {Zafer Selcuk Aygin and Khoa D. Nguyen},
  journal= {arXiv preprint arXiv:2009.02442},
  year   = {2020}
}
R2 v1 2026-06-23T18:19:48.405Z