English

Finite Length for Unramified $GL_2$: Beyond Multiplicity One

Number Theory 2025-05-27 v1

Abstract

Let pp be a prime number and KK a finite unramified extension of Qp\mathbb{Q}_p. Building on recent work of Breuil, Herzig, Hu, Morra and Schraen, we study the smooth mod pp representations of GL2(K)\mathrm{GL}_2(K) appearing in a tower of mod pp Hecke eigenspaces of the cohomology of Shimura curves, under mild genericity assumptions but notably no multiplicity one assumption at tame level, and prove that these representations are of finite length, thereby extending a previous result of the aforementioned authors.

Keywords

Cite

@article{arxiv.2505.20134,
  title  = {Finite Length for Unramified $GL_2$: Beyond Multiplicity One},
  author = {Lucrezia Bertoletti},
  journal= {arXiv preprint arXiv:2505.20134},
  year   = {2025}
}
R2 v1 2026-07-01T02:40:01.791Z