Deformations of reducible Galois representations with large Selmer $p$-rank

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ghate, Eknath, Ray, Anwesh
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913837947551744
author Ghate, Eknath
Ray, Anwesh
author_facet Ghate, Eknath
Ray, Anwesh
contents Let $p\geq 5$ be a prime number. In this paper, we construct Galois representations associated with modular forms for which the dimension of the $p$-torsion in the Bloch-Kato Selmer group can be made arbitrarily large. Our result extends similar results known for small primes, such as Matsuno's work on Tate-Shafarevich groups of elliptic curves. Extending the technique of Hamblen and Ramakrishna, we lift residually reducible Galois representations to modular representations for which the associated Greenberg Selmer groups are minimally generated by a large number of elements over the Iwasawa algebra. We deduce that there is an isogenous lattice for which the Bloch-Kato Selmer group has large $p$-rank.
format Preprint
id arxiv_https___arxiv_org_abs_2504_16287
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Deformations of reducible Galois representations with large Selmer $p$-rank
Ghate, Eknath
Ray, Anwesh
Number Theory
11R23, 11F80
Let $p\geq 5$ be a prime number. In this paper, we construct Galois representations associated with modular forms for which the dimension of the $p$-torsion in the Bloch-Kato Selmer group can be made arbitrarily large. Our result extends similar results known for small primes, such as Matsuno's work on Tate-Shafarevich groups of elliptic curves. Extending the technique of Hamblen and Ramakrishna, we lift residually reducible Galois representations to modular representations for which the associated Greenberg Selmer groups are minimally generated by a large number of elements over the Iwasawa algebra. We deduce that there is an isogenous lattice for which the Bloch-Kato Selmer group has large $p$-rank.
title Deformations of reducible Galois representations with large Selmer $p$-rank
topic Number Theory
11R23, 11F80
url https://arxiv.org/abs/2504.16287