English

Non-Holomorphic Ramanujan-type Congruences for Hurwitz Class Numbers

Number Theory 2022-05-25 v2

Abstract

In contrast to all other known Ramanujan-type congruences, we discover that Ramanujan-type congruences for Hurwitz class numbers can be supported on non-holomorphic generating series. We establish a divisibility result for such non-holomorphic congruences of Hurwitz class numbers. The two keys tools in our proof are the holomorphic projection of products of theta series with a Hurwitz class number generating series and a theorem by Serre, which allows us to rule out certain congruences.

Keywords

Cite

@article{arxiv.2004.06886,
  title  = {Non-Holomorphic Ramanujan-type Congruences for Hurwitz Class Numbers},
  author = {Olivia Beckwith and Martin Raum and Olav K. Richter},
  journal= {arXiv preprint arXiv:2004.06886},
  year   = {2022}
}
R2 v1 2026-06-23T14:51:44.607Z