English

Spectral mod p Satake isomorphism for GL_n

Number Theory 2024-02-22 v1 Representation Theory

Abstract

Let K/QpK/\mathbb{Q}_p be a finite extension with residue field kk. By a work of Emerton--Gee, irreducible components inside the reduced special fiber of the moduli stack of rank nn \'etale (φ,Γ)(\varphi,\Gamma)-modules are labeled by Serre weights of GLn(k)\mathrm{GL}_n(k). Let σ\sigma be a non-Steinberg Serre weight and Cσ\mathcal{C}_\sigma be the corresponding irreducible component. Motivated by the categorical pp-adic local Langlands program, we construct a natural injective map O(Cσ)H(σ)\mathcal{O}(\mathcal{C}_\sigma) \hookrightarrow \mathcal{H}(\sigma) from the ring of global functions on Cσ\mathcal{C}_\sigma to the Hecke algebra of σ\sigma compatible with the mod pp Satake isomorphism by Herzig and Henniart--Vign\'eras in a suitable sense. For sufficiently generic σ\sigma, we prove that it is an isomorphism. As an application, we obtain a natural stratification of the irreducible component whose strata are equipped with a parabolic structure. Our main input is a construction of a morphism from an integral Hecke algebra of a generic tame type to the ring of global functions on a tamely potentially crystalline Emerton--Gee stack.

Keywords

Cite

@article{arxiv.2402.14011,
  title  = {Spectral mod p Satake isomorphism for GL_n},
  author = {Heejong Lee},
  journal= {arXiv preprint arXiv:2402.14011},
  year   = {2024}
}

Comments

36 pages, comments welcome!

R2 v1 2026-06-28T14:56:04.758Z