Arithmetic Satake compactifications and algebraic Drinfeld modular forms

Fuente: arXiv
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Auteurs principaux: Hartl, Urs, Yu, Chia-Fu
Format: Preprint
Publié: 2020
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author Hartl, Urs
Yu, Chia-Fu
author_facet Hartl, Urs
Yu, Chia-Fu
contents In this article we construct the arithmetic Satake compactification of the Drinfeld moduli schemes of arbitrary rank over the ring of integers of any global function field away from the level structure, and show that the universal family extends uniquely to a generalized Drinfeld module over the compactification. Using these and functorial properties, we define algebraic Drinfeld modular forms over more general bases and the action of the (prime-to-residue characteristic and level) Hecke algebra. The construction also furnishes many algebraic Drinfeld modular forms obtained from the coefficients of the universal family which are also Hecke eigenforms. Among them we obtain generalized Hasse invariants which are already defined on the arithmetic Satake compactification and not only its special fiber. We use these generalized Hasse invariants to study the geometry of the special fiber. We conjecture that our Satake compactification is Cohen-Macaulay. If this is the case, we establish the Jacquet-Langlands correspondence (mod $v$) between Hecke eigensystems of rank $r$ Drinfeld modular forms and those of algebraic modular forms (in the sense of Gross) attached to a compact inner form of $GL_r$.
format Preprint
id arxiv_https___arxiv_org_abs_2009_13934
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Arithmetic Satake compactifications and algebraic Drinfeld modular forms
Hartl, Urs
Yu, Chia-Fu
Algebraic Geometry
In this article we construct the arithmetic Satake compactification of the Drinfeld moduli schemes of arbitrary rank over the ring of integers of any global function field away from the level structure, and show that the universal family extends uniquely to a generalized Drinfeld module over the compactification. Using these and functorial properties, we define algebraic Drinfeld modular forms over more general bases and the action of the (prime-to-residue characteristic and level) Hecke algebra. The construction also furnishes many algebraic Drinfeld modular forms obtained from the coefficients of the universal family which are also Hecke eigenforms. Among them we obtain generalized Hasse invariants which are already defined on the arithmetic Satake compactification and not only its special fiber. We use these generalized Hasse invariants to study the geometry of the special fiber. We conjecture that our Satake compactification is Cohen-Macaulay. If this is the case, we establish the Jacquet-Langlands correspondence (mod $v$) between Hecke eigensystems of rank $r$ Drinfeld modular forms and those of algebraic modular forms (in the sense of Gross) attached to a compact inner form of $GL_r$.
title Arithmetic Satake compactifications and algebraic Drinfeld modular forms
topic Algebraic Geometry
url https://arxiv.org/abs/2009.13934