English

Exponential sums over singular binary quartic forms and applications

Number Theory 2024-04-02 v1

Abstract

We investigate exponential sums over singular binary quartic forms, proving an explicit formula for the finite field Fourier transform of this set. Our formula shares much in common with analogous formulas proved previously for other vector spaces, but also exhibits a striking new feature: the point counting function ap(E)=p+1#E(Fp)a_p(E) = p + 1 - \#E(\mathbb{F}_p) associated to an associated elliptic curve makes a prominent appearance. The proof techniques are also new, involving techniques from elementary algebraic geometry and classical invariant theory. As an application to prime number theory, we demonstrate the existence of `many' 2-Selmer elements for elliptic curves with discriminants that are squarefree and have at most four prime factors.

Keywords

Cite

@article{arxiv.2404.00541,
  title  = {Exponential sums over singular binary quartic forms and applications},
  author = {Yasuhiro Ishitsuka and Takashi Taniguchi and Frank Thorne and Stanley Yao Xiao},
  journal= {arXiv preprint arXiv:2404.00541},
  year   = {2024}
}