Date/Time : 04 Nov 2026 13:30
Venue : S16 #05-18
Speaker : Boon Wei Chow, National University of Singapore

For a semisimple adjoint algebraic group acting on a variety, there is a compactification called the wonderful compactification. For the action of PSO(2n) on the symmetric space PSO(2n)/SO(2n-1), the wonderful compactification is the projective space of dimension 2n-1. Huang Daoji showed that there is a stratification and a compatible Bruhat atlas on this wonderful compactification. I will explain how this Bruhat atlas can be made to be compatible with Lusztig’s Total positivity. This is joint work with Huanchen Bao.

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Date/Time : 28 Oct 2026 15:00
Venue : S17 #04-06 (Seminar Room 1)
Speaker : Kari Vilonen, University of Melbourne

I will explain recent joint work with Emerton and Davis. We formulate a conjecture which gives the cohomology of locally symmetric spaces as a cohomology of a coherent sheaf on the side of the Langlands parameters. The description is in terms of the categorical local Langlands. In particular, we explain the Archimedean contribution. We have verified the conjecture in large numbers of cases, for example, it gives the correct answer for the Eisenstein component.

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Date/Time : 28 Oct 2026 16:00
Venue : S17 #04-06 (Seminar Room 1)
Speaker : Ting Xue, University of Melbourne

We explain a uniform construction of cuspidal character sheaves in the setting of Z/mZ-graded Lie algebras. We show that all cuspidal character sheaves arise from the Fourier-Sato transform of nearby cycle sheaves associated to very special supercuspidal data. These data essentially come from Lusztig’s cuspidal character sheaves on (ungraded) reductive Lie algebras. We discuss applications to affine Springer fibres via connection with Lusztig-Yun’s work, where double affine Hecke algebras enter the picture. This is based on joint work with Wille Liu, Cheng-Chiang Tsai and Kari Vilonen.

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Date/Time : 21 Oct 2026 13:00
Venue : S16 #05-18
Speaker : Clifton Cunningham, University of Calgary

Following an idea from the celebrated 1992 book by Adams, Barbasch and Vogan on the Langlands Classification for Real groups, this talk explains that endoscopic transfer for p-adic groups, in great generality, can be understood in terms of equivariant restriction to the fixed-points of a semi-simple automorphism acting on a Vogan variety. To prove this claim, however, requires a fixed-point formula for vanishing cycles of equivariant sheaves on these varieties, recently established by Jörg Schürmann as part of the proof of Vogan’s conjecture for local Arthur packets. In this talk I’ll discuss this theorem and its applications. Joint work with Alexander Hazeltine, Chi-Heng Lo, Baiying Liu, Mishty Ray, Bin Xu and Jörg Schürmann.

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Date/Time : 08 Oct 2026 16:00
Venue : S17 #05-11 (Seminar Room 5)
Speaker : Kyu-Hwan Lee, University of Connecticut

In this talk, we first study murmurations in families of quadratic Dirichlet characters weighted by a smooth compactly supported function. We show that the murmuration density interpolates the phase transition in the one-level density of the associated symplectic family of $L$-functions. Next, we compute the murmuration density for the family of quadratic characters over function fields. We show that its expectation coincides with a correction term arising in the traces of high powers of Frobenius in this family, and we determine the large-genus asymptotics of this term. This correction term admits a description in terms of the stable homology of the moduli space of hyperelliptic curves of genus $g$ with a marked Weierstrass point.

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Date/Time : 07 Oct 2026 13:30
Venue : S16 #05-18
Speaker : Thomas Geisser, Rikkyo University

I will give an overview over properties of motivic cohomology theories and their applications to arithmetic and algebraic geometry. In particular, I plan to cover applications to formulas for special values of zeI will give an overview over properties of motivic cohomology theories and their applications to arithmetic and algebraic geometry. In particular, I plan to cover applications to formulas for special values of zeta-functions, class field theory of schemes, and duality for torsion sheaves.ta-functions, class field theory of schemes, and duality for torsion sheaves.

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Date/Time : 16 Sep 2026 13:30
Venue : S16 #05-18
Speaker : Teruhisa Koshikawa, Keio University

By the categorical local Langlands conjecture, the semiorthogonal decomposition indexed by the Kottwitz set and Bernstein decompositions in the geometric side are expected to have counterparts in the spectral side. I will discuss my joint work with Bertoloni Meli realizing them directly. It is closely related to the theory of cuspidal coherent sheaves, but also has connections to some recent developments in algebraic geometry.

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Date/Time : 09 Sep 2026 13:30
Venue : S16 #05-18
Speaker : Toshihisa Kubo, Ryukoku University

Let X be a smooth manifold and Y a smooth submanifold of X. Let G’ ⊂ G be Lie groups, with G acting on X and G’ acting on Y. A differential operator D from the space of smooth sections of a G-equivariant vector bundle over X and to that of a G’-equivariant vector bundle over Y is called a differential symmetry breaking operator (DSBO for short) if D is G’-intertwining.

In general, the classification and construction of DSBOs are challenging problems. Around 2010, Toshiyuki Kobayashi introduced a fascinating idea for addressing these problems when both X and Y are flag manifolds. We refer to the resulting machinery as the F-method. The F-method reduces the classification and construction of DSBOs to solving a certain system of partial differential equations via the algebraic Fourier transform of generalized Verma modules. In this talk, we shall first discuss recent progress on the F-method. We shall then give explicit formulas for the DSBOs for (G,G’)=(GL(3,R), GL(2,R)) with minimal parabolic subgroups. This talk is based on joint work with Jonathan Ditlevsen and Víctor Pérez-Valdés.

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Date/Time : 19 Aug 2026 13:30
Venue : S16 #05-18
Speaker : Liron Speyer, Okinawa Institute of Science and Technology

I will give a brief account of the combinatorial representation theory of type A Iwahori–Hecke algebras, and their realisation as cyclotomic KLR algebras. In this story, I will largely focus on the decomposition number problem as one of the key problems in this field, and James’s conjecture, which drove a lot of research until Williamson showed it to be false in 2013. While Williamson’s counterexample is incredibly large, and beyond explicit computation, I recently discovered a new counterexample, which is of minimal size. I will explain this counterexample in the talk, as well as touching on how I found it.

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