Jul 11 – 29, 2022
Europe/Paris timezone

Arthur’s Conjectures and the Orbit Method for Real Reductive Groups

Jul 13, 2022, 11:00 AM
1h 20m
Marilyn and James Simons Conference Center (IHES)

Marilyn and James Simons Conference Center


35 route de Chartres, F-91440 Bures-sur-Yvette, France


Prof. Lucas MASON-BROWN (Univ. Oxford)


The most fundamental unsolved problem in the representation theory of Lie groups is the Problem of the Unitary Dual: given a reductive Lie group G, this problem asks for a parameterization of the set of irreducible unitary G-representations. There are two big "philosophies" for approaching this problem. The Orbit Method of Kostant and Kirillov seeks to parameterize irreducible unitary representations in terms of finite covers of co-adjoint G-orbits. Arthur's conjectures suggest a parameterization in terms of certain combinatorial gadgets (i.e. Arthur parameters) related to the Langlands dual group G^{\vee} of G.
In this talk, I will define these correspondences precisely in the case of complex groups. I will also define a natural duality map from Arthur parameters (for G^{\vee}) to co-adjoint covers (for G) which, in a certain precise sense, intertwines these correspondences. This talk is partially based on joint work with Ivan Losev and Dmitryo Matvieievskyi.

Presentation materials