English

Upper bounds on polynomials with small Galois group

Number Theory 2019-10-08 v1

Abstract

When monic integral polynomials of degree n2n \geq 2 are ordered by the maximum of the absolute value of their coefficients, the Hilbert irreducibility theorem implies that asymptotically 100% are irreducible and have Galois group isomorphic to SnS_n. In particular, amongst such polynomials whose coefficients are bounded by BB in absolute value, asymptotically (1+o(1))(2B+1)n(1+o(1))(2B+1)^n are irreducible and have Galois group SnS_n. When GG is a proper transitive subgroup of SnS_n, however, the asymptotic count of polynomials with Galois group GG has been determined only in very few cases. Here, we show that if there are strong upper bounds on the number of degree nn fields with Galois group GG, then there are also strong bounds on the number of polynomials with Galois group GG. For example, for any prime pp, we show that there are at most O(B32p(logB)p1)O(B^{3 - \frac{2}{p}} (\log B)^{p - 1}) polynomials with Galois group CpC_p and coefficients bounded by BB.

Keywords

Cite

@article{arxiv.1910.02122,
  title  = {Upper bounds on polynomials with small Galois group},
  author = {Robert J. Lemke Oliver and Frank Thorne},
  journal= {arXiv preprint arXiv:1910.02122},
  year   = {2019}
}
R2 v1 2026-06-23T11:34:59.440Z