English

Convergence of the Zagier type series for the Cauchy kernel

Algebraic Geometry 2016-02-18 v2 Number Theory

Abstract

In 1975 prof. Don Zagier derived a preliminary formula for the trace of the Hecke operators acting on the space of cusp forms (\cite{5}, \cite{6}). Actually, it is an expression in terms of an integral over a fundamental domain of SL2(Z).SL_2(\mathbb{Z}). His theorem tells us that if ff is a cusp form of weight kk, then we can identify the Peterson scalar product of ff and a certain series ωm(z1,z2ˉ,k)\omega_m(z_1,\bar{z_2}, k) with the action of the Hecke operator T(m)T(m) on the function ff, up to a constant that depends only on kk and mm. It follows that ωm(z1,z2ˉ,k)\omega_m(z_1,\bar{z_2}, k) is kind of "kernel function" for the operator T(m)T(m). Don Zagier proved this theorem using the Rankin-Selberg method. Other evidence was proposed by prof. A. Levin. He suggested to construct a Cauchy kernel. Formally, the Cauchy kernel expressed by the series, which doesn't converge absolutely. The main purpose of this paper is to extend this series to the edge of convergence by analytic continuation. The second part of the paper is devoted to getting an expression for differential form of logarithm of difference of two jj-invariant values j(z1)j(z2)|j(z_1)-j(z_2)|.

Keywords

Cite

@article{arxiv.1503.05503,
  title  = {Convergence of the Zagier type series for the Cauchy kernel},
  author = {Nina Sakharova},
  journal= {arXiv preprint arXiv:1503.05503},
  year   = {2016}
}