English

Traces of partition Eisenstein series

Number Theory 2025-02-05 v4

Abstract

We study "partition Eisenstein series", extensions of the Eisenstein series G2k(τ),G_{2k}(\tau), defined by λ=(1m1,2m2,,kmk)k          Gλ(τ):=G2(τ)m1G4(τ)m2G2k(τ)mk.\lambda=(1^{m_1}, 2^{m_2},\dots, k^{m_k}) \vdash k \ \ \ \ \ \longmapsto \ \ \ \ \ G_{\lambda}(\tau):= G_2(\tau)^{m_1} G_4(\tau)^{m_2}\cdots G_{2k}(\tau)^{m_k}. For functions ϕ:PC\phi: \mathcal{P}\rightarrow \mathbb{C} on partitions, the weight 2k2k "partition Eisenstein trace" is the quasimodular form Trk(ϕ;τ):=λkϕ(λ)Gλ(τ). {\mathrm{Tr}}_k(\phi;\tau):=\sum_{\lambda \vdash k} \phi(\lambda)G_{\lambda}(\tau). These traces give explicit formulas for some well-known generating functions, such as the kkth elementary symmetric functions of the inverse points of 2-dimensional complex lattices ZZτ,\mathbb{Z}\oplus \mathbb{Z}\tau, as well as the 2k2kth power moments of the Andrews-Garvan crank function. To underscore the ubiquity of such traces, we show that their generalizations give the Taylor coefficients of generic Jacobi forms with torsional divisor.

Keywords

Cite

@article{arxiv.2408.08807,
  title  = {Traces of partition Eisenstein series},
  author = {Tewodros Amdeberhan and Michael Griffin and Ken Ono and Ajit Singh},
  journal= {arXiv preprint arXiv:2408.08807},
  year   = {2025}
}

Comments

A few typos fixed