A Modular Interpretation of BBGS Towers
Abstract
In 2000, based on his procedure for constructing explicit towers of modular curves, Elkies deduced explicit equations of rank-2 Drinfeld modular curves which coincide with the asymptotically optimal towers of curves constructed by Garcia and Stichtenoth. In 2015, Bassa, Beelen, Garcia, and Stichtenoth constructed a celebrated (recursive and good) tower (BBGS-tower for short) of curves and outlined a modular interpretation of the defining equations. Soon after that, Gekeler studied in depth the modular curves coming from sparse Drinfeld modules. In this paper, to establish a link between these existing results, we propose and prove a generalized Elkies' Theorem which tells in detail how to directly describe a modular interpretation of the equations of rank-m Drinfeld modular curves with m>=2.
Cite
@article{arxiv.1912.02668,
title = {A Modular Interpretation of BBGS Towers},
author = {Rui Chen and Zhuo Chen and Chuangqiang Hu},
journal= {arXiv preprint arXiv:1912.02668},
year = {2020}
}
Comments
revised the paper with the intention of presenting a correct and clear version