English

Multivariable ($\varphi$,$\mathcal{O}_K^\times$)-modules and local-global compatibility

Number Theory 2025-06-13 v4 Representation Theory

Abstract

Let pp be a prime number, KK a finite unramified extension of Qp\mathbb{Q}_p and F\mathbb{F} a finite extension of Fp\mathbb{F}_p. Using perfectoid spaces we associate to any finite-dimensional continuous representation ρ\overline{\rho} of Gal(K/K){\rm Gal}(\overline K/K) over F\mathbb{F} an \'etale (φ,OK×)(\varphi,\mathcal{O}_K^\times)-module DA(ρ)D_A^\otimes(\overline{\rho}) over a completed localization AA of F[ ⁣[OK] ⁣]\mathbb{F}[\![\mathcal{O}_K]\!]. We conjecture that one can also associate an \'etale (φ,OK×)(\varphi,\mathcal{O}_K^\times)-module DA(π)D_A(\pi) to any smooth representation π\pi of GL2(K)\mathrm{GL}_2(K) occurring in some Hecke eigenspace of the mod pp cohomology of a Shimura curve, and that moreover DA(π)D_A(\pi) is isomorphic (up to twist) to DA(ρ)D_A^\otimes(\overline{\rho}), where ρ\overline{\rho} is the underlying 22-dimensional representation of Gal(K/K){\rm Gal}(\overline K/K). Using previous work of the same authors, we prove this conjecture when ρ\overline{\rho} is semi-simple and sufficiently generic.

Keywords

Cite

@article{arxiv.2211.00438,
  title  = {Multivariable ($\varphi$,$\mathcal{O}_K^\times$)-modules and local-global compatibility},
  author = {Christophe Breuil and Florian Herzig and Yongquan Hu and Stefano Morra and Benjamin Schraen},
  journal= {arXiv preprint arXiv:2211.00438},
  year   = {2025}
}

Comments

Minor modifications after the referee report

R2 v1 2026-06-28T04:55:34.891Z