A variant of Harish-Chandra functors

Tyrone Crisp, Ehud Meir, Uri Onn

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Abstract

Harish-Chandra induction and restriction functors play a key role in the representation theory of reductive groups over finite fields. In this paper, extending earlier work of Dat, we introduce and study generalisations of these functors which apply to a wide range of finite and profinite groups, typical examples being compact open subgroups of reductive groups over non-archimedean local fields. We prove that these generalisations are compatible with two of the tools commonly used to study the (smooth, complex) representations of such groups, namely Clifford theory and the orbit method. As a test case, we examine in detail the induction and restriction of representations from and to the Siegel Levi subgroup of the symplectic group $\text{Sp}_{4}$ over a finite local principal ideal ring of length two. We obtain in this case a Mackey-type formula for the composition of these induction and restriction functors which is a perfect analogue of the well-known formula for the composition of Harish-Chandra functors. In a different direction, we study representations of the Iwahori subgroup $I_{n}$ of $\text{GL}_{n}(F)$ , where $F$ is a non-archimedean local field. We establish a bijection between the set of irreducible representations of $I_{n}$ and tuples of primitive irreducible representations of smaller Iwahori subgroups, where primitivity is defined by the vanishing of suitable restriction functors.
Original languageEnglish
Number of pages57
JournalJournal of the Institute of Mathematics of Jussieu
Early online date14 Aug 2017
DOIs
Publication statusE-pub ahead of print - 14 Aug 2017

Fingerprint

Functor
Subgroup
Restriction
Proof by induction
Reductive Group
Local Field
Irreducible Representation
Clifford Theory
Profinite Groups
Symplectic Group
Group Theory
Representation Theory
Bijection
Galois field
Finite Group
Orbit
Analogue
Ring
Range of data
Generalization

Keywords

  • Harish-Chandra induction
  • parabolic induction
  • compact p-adic groups
  • representations of profinite groups

Cite this

A variant of Harish-Chandra functors. / Crisp, Tyrone; Meir, Ehud; Onn, Uri.

In: Journal of the Institute of Mathematics of Jussieu, 14.08.2017.

Research output: Contribution to journalArticle

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