Local Langlands in families: The banal case
4 affiliations
- 1IMJ-PRG , Sorbonne Université , Université Paris Cité, CNRS, 4 Place Jussieu, 75005 , Paris , France
- 2Department of Mathematics , Imperial College , London , SW7 2AZ , United Kingdom
- 3School of Mathematics and Statistics , University of Sheffield , Sheffield , S3 7RH , United Kingdom
- 4Department of Mathematics & Statistics , University of Maine , 5752 Neville Hall , Orono , ME 04469 , USA
Abstract
We state a conjecture, local Langlands in families , connecting the centre of the category of smooth representations on Z [ q − 1 ] \mathbb{Z}[\sqrt{q}^{-1}] -modules of a quasi-split 𝑝-adic group G \mathrm{G} (where 𝑞 is the cardinality of the residue field of the underlying local field), the ring of global functions on the stack of Langlands parameters for G \mathrm{G} over Z [ q − 1 ] \mathbb{Z}[\sqrt{q}^{-1}] , and the endomorphisms of a Gelfand–Graev representation for G \mathrm{G} . For a class of classical 𝑝-adic groups (symplectic, unitary, or odd special orthogonal groups), we prove this conjecture after inverting an integer depending only on G \mathrm{G} . Along the way, we show that the local Langlands correspondence for classical 𝑝-adic groups (1) preserves integrality of ℓ-adic representations, (2) satisfies an “extended” (generic) packet conjecture, (3) is compatible with parabolic induction up to semisimplification (generalizing a result of Moussaoui), hence induces a semisimple local Langlands correspondence, and (4) the semisimple correspondence is compatible with automorphisms of ℂ fixing q \sqrt{q} .
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BibTeX
@article{dat2026local,
title = {{Local Langlands in families: The banal case}},
author = {Jean-François Dat and David Helm and Robert Kurinczuk and Gilbert Moss},
journal = {Journal für die reine und angewandte Mathematik (Crelles Journal)},
year = {2026},
month = may,
doi = {10.1515/crelle-2026-0034},
url = {https://doi.org/10.1515/crelle-2026-0034},
note = {CC BY},
}
RIS
TY - JOUR
TI - Local Langlands in families: The banal case
AU - Jean-François Dat
AU - David Helm
AU - Robert Kurinczuk
AU - Gilbert Moss
PY - 2026
DA - 2026/05/20
JO - Journal für die reine und angewandte Mathematik (Crelles Journal)
DO - 10.1515/crelle-2026-0034
UR - https://doi.org/10.1515/crelle-2026-0034
AB - We state a conjecture, local Langlands in families , connecting the centre of the category of smooth representations on Z [ q − 1 ] \mathbb{Z}[\sqrt{q}^{-1}] -modules of a quasi-split 𝑝-adic group G \mathrm{G} (where 𝑞 is the cardinality of the residue field of the underlying local field), the ring of global functions on the stack of Langlands parameters for G \mathrm{G} over Z [ q − 1 ] \mathbb{Z}[\sqrt{q}^{-1}] , and the endomorphisms of a Gelfand–Graev representation for G \mathrm{G} . For a class of classical 𝑝-adic groups (symplectic, unitary, or odd special orthogonal groups), we prove this conjecture after inverting an integer depending only on G \mathrm{G} . Along the way, we show that the local Langlands correspondence for classical 𝑝-adic groups (1) preserves integrality of ℓ-adic representations, (2) satisfies an “extended” (generic) packet conjecture, (3) is compatible with parabolic induction up to semisimplification (generalizing a result of Moussaoui), hence induces a semisimple local Langlands correspondence, and (4) the semisimple correspondence is compatible with automorphisms of ℂ fixing q \sqrt{q} .
SN - 0075-4102
SN - 1435-5345
ER -