Skip to Main Content


AMS eBook CollectionsOne of the world's most respected mathematical collections, available in digital format for your library or institution


To an effective local Langlands Correspondence

About this Title

Colin J. Bushnell, King’s College London, Department of Mathematics, Strand, London WC2R 2LS, UK. and Guy Henniart, Université de Paris-Sud, Laboratoire de Mathématiques d’Orsay, Orsay Cedex, F-91405; CNRS, Orsay cedex, F-91405.

Publication: Memoirs of the American Mathematical Society
Publication Year: 2014; Volume 231, Number 1087
ISBNs: 978-0-8218-9417-0 (print); 978-1-4704-1723-9 (online)
DOI: https://doi.org/10.1090/memo/1087
Published electronically: February 10, 2014
Keywords: Explicit local Langlands correspondence, automorphic induction, simple type
MSC: Primary 22E50

View full volume PDF

View other years and numbers:

Table of Contents

Chapters

  • Introduction
  • 1. Representations of Weil groups
  • 2. Simple characters and tame parameters
  • 3. Action of tame characters
  • 4. Cuspidal representations
  • 5. Algebraic induction maps
  • 6. Some properties of the Langlands correspondence
  • 7. A naïve correspondence and the Langlands correspondence
  • 8. Totally ramified representations
  • 9. Unramified automorphic induction
  • 10. Discrepancy at a prime element
  • 11. Symplectic signs
  • 12. Main Theorem and examples

Abstract

Let $F$ be a non-Archimedean local field. Let $\mathcal {W}_{F}$ be the Weil group of $F$ and $\mathcal {P}_{F}$ the wild inertia subgroup of $\mathcal {W}_{F}$. Let $\widehat {\mathcal {W}}_{F}$ be the set of equivalence classes of irreducible smooth representations of $\mathcal {W}_{F}$. Let $\mathcal {A}^{0}_{n}(F)$ denote the set of equivalence classes of irreducible cuspidal representations of $\mathrm {GL}_{n}(F)$ and set $\widehat {\mathrm {GL}}_{F} = \bigcup _{n\ge 1} \mathcal {A}^{0}_{n}(F)$. If $\sigma \in \widehat {\mathcal {W}}_{F}$, let $^{L}{\sigma }\in \widehat {\mathrm {GL}}_{F}$ be the cuspidal representation matched with $\sigma$ by the Langlands Correspondence. If $\sigma$ is totally wildly ramified, in that its restriction to $\mathcal {P}_{F}$ is irreducible, we treat $^{L}{\sigma }$ as known. From that starting point, we construct an explicit bijection $\mathbb {N}:\widehat {\mathcal {W}}_{F} \to \widehat {\mathrm {GL}}_{F}$, sending $\sigma$ to $^{N}{\sigma }$. We compare this “naïve correspondence” with the Langlands correspondence and so achieve an effective description of the latter, modulo the totally wildly ramified case. A key tool is a novel operation of “internal twisting” of a suitable representation $\pi$ (of $\mathcal {W}_{F}$ or $\mathrm {GL}_{n}(F)$) by tame characters of a tamely ramified field extension of $F$, canonically associated to $\pi$. We show this operation is preserved by the Langlands correspondence.

References [Enhancements On Off] (What's this?)

References