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Main Author: Zhang, Xinyao
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.21249
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author Zhang, Xinyao
author_facet Zhang, Xinyao
contents In this article, we study the Zariski closure of modular points in the two-dimensional universal deformation space when the residual Galois representation is reducible. Unlike the previous approaches in the residually irreducible case from Gouvêa-Mazur, Böckle and Allen, our method relies on local-global compatibility results, potential pro-modularity arguments and a non-ordinary finiteness result between the local deformation ring at $p$ and the global deformation ring. This allows us to construct sufficiently many non-ordinary regular de Rham points whose modularity is guaranteed by the recent progress on the Fontaine-Mazur conjecture. Also, we will discuss some applications of our main results, including the equidimensionality of certain big Hecke algebras and big $R=\mathbb{T}$ theorems in the residually reducible case.
format Preprint
id arxiv_https___arxiv_org_abs_2512_21249
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Zariski density of modular points in the Eisenstein case
Zhang, Xinyao
Number Theory
In this article, we study the Zariski closure of modular points in the two-dimensional universal deformation space when the residual Galois representation is reducible. Unlike the previous approaches in the residually irreducible case from Gouvêa-Mazur, Böckle and Allen, our method relies on local-global compatibility results, potential pro-modularity arguments and a non-ordinary finiteness result between the local deformation ring at $p$ and the global deformation ring. This allows us to construct sufficiently many non-ordinary regular de Rham points whose modularity is guaranteed by the recent progress on the Fontaine-Mazur conjecture. Also, we will discuss some applications of our main results, including the equidimensionality of certain big Hecke algebras and big $R=\mathbb{T}$ theorems in the residually reducible case.
title Zariski density of modular points in the Eisenstein case
topic Number Theory
url https://arxiv.org/abs/2512.21249