English

From pro-$p$ Iwahori-Hecke modules to $(\varphi,\Gamma)$-modules I

Number Theory 2016-06-08 v1

Abstract

Let o{\mathfrak o} be the ring of integers in a finite extension KK of Qp{\mathbb Q}_p, let kk be its residue field. Let GG be a split reductive group over Qp{\mathbb Q}_p, let TT be a maximal split torus in GG. Let H(G,I0){\mathcal H}(G,I_0) be the pro-pp-Iwahori Hecke o{\mathfrak o}-algebra. Given a semiinfinite reduced chamber gallery (alcove walk) C()C^{({\bullet})} in the TT-stable apartment, a period ϕN(T)\phi\in N(T) of C()C^{({\bullet})} of length rr and a homomorphism τ:Zp×T\tau:{\mathbb Z}_p^{\times}\to T compatible with ϕ\phi, we construct a functor from the category Modfin(H(G,I0)){\rm Mod}^{\rm fin}({\mathcal H}(G,I_0)) of finite length H(G,I0){\mathcal H}(G,I_0)-modules to \'{e}tale (φr,Γ)(\varphi^r,\Gamma)-modules over Fontaine's ring OE{\mathcal O}_{\mathcal E}. If G=GLd+1(Qp)G={\rm GL}_{d+1}({\mathbb Q}_p) there are essentially two choices of (C()C^{({\bullet})}, ϕ\phi, τ\tau) with r=1r=1, both leading to a functor from Modfin(H(G,I0)){\rm Mod}^{\rm fin}({\mathcal H}(G,I_0)) to \'{e}tale (φ,Γ)(\varphi,\Gamma)-modules and hence to GalQp{\rm Gal}_{{\mathbb Q}_p}-representations. Both induce a bijection between the set of absolutely simple supersingular H(G,I0)ok{\mathcal H}(G,I_0)\otimes_{\mathfrak o} k-modules of dimension d+1d+1 and the set of irreducible representations of GalQp{\rm Gal}_{{\mathbb Q}_p} over kk of dimension d+1d+1. We also compute these functors on modular reductions of tamely ramified locally unitary principal series representations of GG over KK. For d=1d=1 we recover Colmez' functor (when restricted to o{\mathfrak o}-torsion GL2(Qp){\rm GL}_{2}({\mathbb Q}_p)-representations generated by their pro-pp-Iwahori invariants)

Keywords

Cite

@article{arxiv.1507.05859,
  title  = {From pro-$p$ Iwahori-Hecke modules to $(\varphi,\Gamma)$-modules I},
  author = {Elmar Grosse-Klönne},
  journal= {arXiv preprint arXiv:1507.05859},
  year   = {2016}
}
R2 v1 2026-06-22T10:15:42.963Z