English

Multiplicity one for wildly ramified representations

Number Theory 2019-10-16 v2

Abstract

Let FF be a totally real field in which pp is unramified. Let r:GFGL2(Fp)\overline{r}: G_F \rightarrow \mathrm{GL}_2(\overline{\mathbb{F}}_p) be a modular Galois representation which satisfies the Taylor-Wiles hypotheses and is generic at a place vv above pp. Let m\mathfrak{m} be the corresponding Hecke eigensystem. Then the m\mathfrak{m}-torsion in the mod pp cohomology of Shimura curves with full congruence level at vv coincides with the GL2(kv)\mathrm{GL}_2(k_v)-representation D0(rGFv)D_0(\overline{r}|_{G_{F_v}}) constructed by Breuil and Pa\v{s}k\={u}nas. In particular, it depends only on the local representation rGFv\overline{r}|_{G_{F_v}}, and its Jordan-H\"older factors appear with multiplicity one. This builds on and extends work of the author with Morra and Schraen and independently of Hu-Wang, which proved these results when rGFv\overline{r}|_{G_{F_v}} was additionally assumed to be tamely ramified. The main new tool is a method for computing Taylor-Wiles patched modules of integral projective envelopes using multitype tamely potentially Barsotti-Tate deformation rings and their intersection theory.

Keywords

Cite

@article{arxiv.1708.04582,
  title  = {Multiplicity one for wildly ramified representations},
  author = {Daniel Le},
  journal= {arXiv preprint arXiv:1708.04582},
  year   = {2019}
}

Comments

20 pages

R2 v1 2026-06-22T21:15:19.990Z