English

A classification of harmonic Maass forms

Number Theory 2016-09-23 v1

Abstract

We give a classification of the Harish-Chandra modules generated by the pullback to SL2(R)\text{SL}_2(\mathbb R) of harmonic Maass forms for congruence subgroups of SL2(Z)\text{SL}_2(\mathbb Z) with exponential growth allowed at the cusps. We assume that the weight is integral but include vector-valued forms. Due to the weak growth condition, these modules need not be irreducible. Elementary Lie algebra considerations imply that there are 9 possibilities, and we show, by giving explicit examples, that all of them arise from harmonic Maass forms. Finally, we briefly discuss the case of forms that are not harmonic but rather are annihilated by a power of the Laplacian, where much more complicated Harish-Chandra modules can arise.

Keywords

Cite

@article{arxiv.1609.06999,
  title  = {A classification of harmonic Maass forms},
  author = {Kathrin Bringmann and Stephen Kudla},
  journal= {arXiv preprint arXiv:1609.06999},
  year   = {2016}
}
R2 v1 2026-06-22T15:58:00.834Z