English

Convolution and square in abelian groups I

Number Theory 2022-08-04 v2

Abstract

We prove that on the cyclic groups of odd order d, there exist non zero functions whose convolution square f*f(2t) is proportional to their square f(t)^2 when the proportionality constant is given by an imaginary quadratic integer of norm d which is equal to 1 modulo 2. The proof involves theta functions on elliptic curves with complex multiplication.

Keywords

Cite

@article{arxiv.2205.08749,
  title  = {Convolution and square in abelian groups I},
  author = {Yves Benoist},
  journal= {arXiv preprint arXiv:2205.08749},
  year   = {2022}
}
R2 v1 2026-06-24T11:20:44.764Z