English

On the $p$-rationality of consecutive quadratic fields

Number Theory 2022-08-09 v1

Abstract

In 2016, in the work related to Galois representations, Greenberg conjectured the existence of multi-quadratic pp-rational number fields of degree 2t2^{t} for any odd prime number pp and any integer t1t \geq 1. Using the criteria provided by him to check pp-rationality for abelian number fields, certain infinite families of quadratic, biquadratic and triquadratic pp-rational fields have been shown to exist in recent years. In this article, for any integer k1k \geq 1, we build upon the existing work and prove the existence of infinitely many prime numbers pp for which the imaginary quadratic fields Q((p1)),,Q((pk))\mathbb{Q}(\sqrt{-(p - 1)}),\ldots,\mathbb{Q}(\sqrt{-(p - k)}) and Q(p(p1)),,Q(p(pk))\mathbb{Q}(\sqrt{-p(p - 1)}),\ldots, \mathbb{Q}(\sqrt{-p(p - k)}) are all pp-rational. This can be construed as analogous results in the spirit of Iizuka's conjecture on the divisibility of class numbers of consecutive quadratic fields. We also address a similar question of pp-rationality for two consecutive real quadratic fields by proving the existence of infinitely many pp-rational fields of the form Q(p2+1)\mathbb{Q}(\sqrt{p^{2} + 1}) and Q(p2+2)\mathbb{Q}(\sqrt{p^{2} + 2}). The result for imaginary quadratic fields is accomplished by producing infinitely many primes for which the corresponding consecutive discriminants have large square divisors and the same for real quadratic fields is proven using a result of Heath-Brown on the density of square-free values of polynomials at prime arguments.

Keywords

Cite

@article{arxiv.2208.04214,
  title  = {On the $p$-rationality of consecutive quadratic fields},
  author = {Jaitra Chattopadhyay and H Laxmi and Anupam Saikia},
  journal= {arXiv preprint arXiv:2208.04214},
  year   = {2022}
}

Comments

10 pages, 3 tables. Comments are welcome