English

The least prime with a given cycle type

Number Theory 2026-01-01 v1

Abstract

Let GG be a finite group. Let K/kK/k be a Galois extension of number fields with Galois group isomorphic to GG, and let CGal(K/k)GC \subseteq \mathrm{Gal}(K/k) \simeq G be a conjugacy invariant subset. It is well known that there exists an unramified prime ideal p\mathfrak{p} of kk with Frobenius element lying in CC and norm satisfying NpDisc(K)α\mathrm{N}\mathfrak{p} \ll |\mathrm{Disc}(K)|^{\alpha} for some constant α=α(G,C)\alpha = \alpha(G,C). There is a rich literature establishing unconditional admissible values for α\alpha, with most approaches proceeding by studying the zeros of LL-functions. We give an alternative approach, not relying on zeros, that often substantially improves this exponent α\alpha for any fixed finite group GG, provided CC is a union of rational equivalence classes. As a particularly striking example, we prove that there exist absolute constants c1,c2>0c_1,c_2 > 0 such that for any n2n\geq 2 and any conjugacy class CSnC \subset S_n, one may take α(Sn,C)=c1exp(c2n)\alpha(S_n,C) = c_1 \exp(-c_2n). Our approach reduces the core problem to a question in character theory.

Keywords

Cite

@article{arxiv.2512.24963,
  title  = {The least prime with a given cycle type},
  author = {Peter J. Cho and Robert J. Lemke Oliver and Asif Zaman},
  journal= {arXiv preprint arXiv:2512.24963},
  year   = {2026}
}

Comments

44 pages, 9 tables

R2 v1 2026-07-01T08:47:05.804Z