English

Square-free orders for CM elliptic curves modulo $p$ in short intervals

Number Theory 2025-10-30 v2

Abstract

Let EE be a CM elliptic curve over Q\Bbb{Q}. We refine the work of Cojocaru on the asymptotic formulae for the number of primes pxp\le x for which the reduction modulo pp of EE is of square-free order. Also, we derive an unconditional short interval variant for the asymptotics. Compared to the estimate derived from the generalised Riemann hypothesis, the presented result is valid for even shorter intervals. Furthermore, we improve the short interval variant of the cyclicity problem for CM elliptic curves previously obtained by the author.

Keywords

Cite

@article{arxiv.2408.05904,
  title  = {Square-free orders for CM elliptic curves modulo $p$ in short intervals},
  author = {Peng-Jie Wong},
  journal= {arXiv preprint arXiv:2408.05904},
  year   = {2025}
}

Comments

Accepted by Math. Z

R2 v1 2026-06-28T18:10:02.561Z