English

Deformations of Certain Reducible Galois Representations, III

Number Theory 2022-02-24 v5

Abstract

Let pp be an odd prime and qq a power of pp. We examine the deformation theory of reducible and indecomposable Galois representations ρˉ:GQGSp2n(Fq)\bar{\rho}:G_{\mathbb{Q}}\rightarrow \text{GSp}_{2n}(\mathbb{F}_q) that are unramified outside a finite set of primes SS and whose image lies in a Borel subgroup. We show that under some additional hypotheses, such representations have geometric lifts to the Witt vectors W(Fq)\text{W}(\mathbb{F}_q). The main theorem extends that of Hamblen and Ramakrishna in which the n=1n=1 case was treated.

Keywords

Cite

@article{arxiv.1812.04671,
  title  = {Deformations of Certain Reducible Galois Representations, III},
  author = {Anwesh Ray},
  journal= {arXiv preprint arXiv:1812.04671},
  year   = {2022}
}

Comments

Final version, to appear in IJNT. 49 pages, relaxed hypotheses of main theorem, provided examples