Representations of p-adic groups and related topics

One-day in-person meeting on 14 September 2021

Department of Mathematical Sciences, Durham University

Organiser: Alexander Stasinski

Speakers

Jack Shotton (Durham)

Beth Romano (Oxford)

Emile Okada (Oxford)

Robert Kurinczuk (Sheffield)


The meeting is funded by the EPSRC programme grant "Symmetries and Correspondences".

Programme

All the talks will take place in room MCS2068.

9:30 - 10:30 Jack Shotton (Durham)

Local deformation rings and endomorphisms of Gelfand-Graev representations

I will describe some results on the structure of moduli spaces of Galois representations (in the '\ell \neq p' case) at generic points on a large subset of components of their special fibres. They will be smooth over a certain ring of invariants. I will then explain a conjecture that this ring coincides with the endomorphism ring of an integral Gelfand-Graev representation, and give some partial results towards it.

Break

11:00 - 12:00 Beth Romano (Oxford)

A Fourier transform for unipotent representations of p-adic groups

Representations of finite reductive groups have a rich, well-understood structure, first explored by Deligne--Lusztig. In joint work with Anne-Marie Aubert and Dan Ciubotaru, we show a way to lift some of this structure to representations of p-adic groups. In particular, we work with the class of unipotent representations of split p-adic groups, and consider the relation between Lusztig's nonabelian Fourier transform and a certain involution we define on the level of p-adic groups. This talk will be an introduction to these ideas via examples; I will not assume previous familiarity with these topics.

Lunch

14:00 - 15:00 Emile Okada (Oxford)

The wavefront set of admissible representations of p-adic groups.

Abstract: The wavefront set is a powerful invariant which one can attach to representations of p-adic groups with applications to the structure of automorphic representations, branching laws, and Fourier coefficients of automorphic forms. In this talk we will discuss the basic definitions and properties of the wavefront set, followed by methods for computing it, and finally if time permits, some recent advances connecting the wavefront set to equivariant perverse sheaves on the complex dual group.

Break

15:30 - 16:30 Robert Kurinczuk (Sheffield)

Local Langlands in families for classical groups

The conjectural local Langlands correspondence connects representations of p-adic groups to certain representations of Galois groups of local fields called Langlands parameters.  In recent joint work with Dat, Helm, and Moss, we have constructed moduli spaces of Langlands parameters over Z[1/p] and studied their geometry.  We expect this geometry is reflected in the representation theory of the p-adic group.  Our main conjecture “local Langlands in families” describes the GIT quotient of the moduli space of Langlands parameters in terms of the centre of the category of representations of the p-adic group generalising a theorem of Helm-Moss for GL(n).  I will explain how after inverting the "non-banal primes" one can prove this conjecture for the local Langlands correspondences of Arthur and others .

18:00 Dinner