English

The Universal Elliptic KZB Connection in Higher Level

Algebraic Geometry 2022-07-26 v3 Number Theory

Abstract

The level NN elliptic KZB connection is a flat connection over the universal elliptic curve in level NN with its NN-torsion sections removed. Its fiber over the point (E,x)(E,x) is the unipotent completion of π1(EE[N],x)\pi_1(E - E[N],x). It was constructed by Calaque and Gonzalez. In this paper, we show that the connection underlies an admissible variation of mixed Hodge structure and that it degenerates to the cyclotomic KZ connection over the singular fibers of the compactified universal elliptic curve. These are the first steps in a larger project to compute the action of the Galois group of mixed Tate motives unramified over Z[μN,1/N]\mathbb{Z}[\mathbf{\mu}_N,1/N] on the unipotent fundamental group of P1{0,μN,}\mathbb{P}^1 - \{0,\mathbf{\mu}_N,\infty\} and to better understand Goncharov's higher cyclotomy.

Cite

@article{arxiv.2107.14320,
  title  = {The Universal Elliptic KZB Connection in Higher Level},
  author = {Eric Hopper},
  journal= {arXiv preprint arXiv:2107.14320},
  year   = {2022}
}

Comments

Revised after referee report: citations added and several minor formulas corrected

R2 v1 2026-06-24T04:40:10.008Z