K-Theory and Representation Theory

REAL

14/07/2021 - 22/07/2022

Organisers:

Nigel Higson (Penn State)
Roger Plymen (Manchester)
Haluk Sengun (Sheffield)

EVENT OVERVIEW

This is a synergistic intra-disciplinary symposium that will focus on new and developing links between operator K-theory and representation theory.

summary

This is a synergistic, intra-disciplinary symposium that will focus on new and developing links between operator K-theory and representation theory.

 

The meeting will consider the following threads:

 

Recent advances in operator K-theory and representation theory for affine Hecke algebras and p-adic groups (including the local Langlands correspondence). In a series works, Plymen and collaborators have constructed a conjectural, and partly proven, bridge (known as the ABPS conjecture) between the K-theory of the reduced group C*-algebra of a p-adic group G and the parametrization (a la Bernstein) of the tempered dual of G. This conjecture relates intimately to the Langlands parameters and thus is of relevance to a wide group of researchers.

 

New constructions linking K-theory, trace formula and automorphic forms. In recent works, Mesland and Sengun constructed a KK-theoretic counterpart of the Hecke ring of Shimura. This contruction endowed many K-groups associated to arithmetic groups (such as group C*-algebras and boundary cross product algebras) with the action of the Hecke ring. Could these new K-theoretic Hecke modules play a role similar to that of the cohomology of arithmetic groups in the theory of automorphic forms?

 

New approaches to tempered representation theory for real Lie groups via operator algebras and noncommutative geometry. In recent works, Higson and collaborators have pioneered  approaches to parabolic induction in the tempered representation theory of reductive groups via Hilbert C*-modules, and approaches to the tempered dual in full via the Mackey bijection.

 

Emerging approaches to the topological aspects of harmonic analysis on reductive symmetric spaces. Given a quotient X=G/H of a real reductive group by the fixed points of an involution on that group, the spectrum of L2(X) as a G-representation is well-understood by harmonic analysis as a measure space. The recent interactions indicated that there is a promising possibility to study the spectrum topologically, using C*-algebras and K-theory.

 

We plan to push further the synergistic aspects of the meeting by bringing together a balance of experts who work in representation theory and harmonic analysis, with experts in noncommutative geometry and operator K-theory.  Speakers will be encouraged to present open problems accessible across boundaries, and touch on possible new points of contact between the above research threads.

Speaker List

Alexandre Afgoustidis (Metz)

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Anne-Marie Aubert (Paris)

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Peter Hochs (Nijmegen)

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Bram Mesland (Leiden)

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Shintaro Nishikawa (Muenster)

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Beth Romano (Oxford)

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Henrik Schlichtkrull (Copenhagen)

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Shu Shen (Paris)

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Maarten Solleveld (Nijmegen)

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Yanli Song (st Louis)

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Shaun Stevens (East Anglia)

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Michele Vergne (Paris)

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Hang Wang (Shanghai)

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Nick Wright (Southampton)

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