The seminar will meet at 4:00–5:00 pm, Wednesday (almost) every week during semesters, in the lecture room of IASM (East 7 Bldg, Zijingang Campus), unless otherwise noted. The seminar is organized by the NT&RT Group at Zhejiang University.

Here are the past talks.

Click on a title to reveal its abstract.

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Schedule (2026–27 Fall)

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Sep 9

• Speaker: Jack Sempliner (University of California, Los Angeles)
• Title: On a cohomological Jacquet–Langlands correspondence for Shimura varieties
• We will discuss a new result on the p-adic geometry of Igusa stacks, which allows one to relate the p-adic geometry of Shimura varieties for a pair of groups G, G' which are global extended pure inner forms. Using this geometric input and the spectral action of Fargues–Scholze, we will discuss how this input may be used to prove the existence of Hecke-equivariant cohomological "Jacquet–Langlands" maps between the cohomology (even with integral or torsion coefficients) of the two Shimura varieties of abelian type associated to G, G'.

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Sep 16

• Speaker: Fernando Trejos (Princeton University)
• Title: An Euler system for the triple product
• We discuss the construction of an Euler system for the "triple product:" the 8-dimensional p-adic Galois representation V = V_1 x V_2 x V_3, where V_i for i=1,2,3 is the representation attached to an ordinary cuspidal eigenform f_i of weight k_i (varying in a Hida family). Our construction is via the pullback method recently introduced by Sangiovanni Vincentelli and Skinner. The image of the Euler system under a Perrin-Riou regulator map is the p-adic L-function of Hsieh and Yamana that interpolates critical values of L(f_1 x f_2 x f_3 x \chi, s), where \chi is a Dirichlet character and the weights (k_1, k_2, k_3) are in the balanced range. The cyclotomic variable \chi is not seen by previous constructions, such as the diagonal cycles of Darmon and Rotger.

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Sep 23 (Two talks!)

• Speaker: Naoki Imai 今井直毅 (University of Tokyo 東京大学)
• Title: (15:15–16:15) Toward finite-local compatibility in the Langlands program
• A finite field analogue of the Langlands correspondence was recently formulated in joint work with David Vogan. In this talk, we will discuss its construction and conjectural relationship with the categorical local Langlands correspondence.

• Speaker: Xinwen Zhu 朱歆文 (Stanford University)
• Title: (16:30–17:30) Deligne–Lusztig theory for Jacobi groups
• I will discuss the Deligne–Lusztig theory for Jacobi groups, by which I mean non-reductive groups of the form G=H \times M, where H is the Heisenberg group attached to a symplectic vector space (V,\eta) and M is a reductive group acting on (V,\eta). I will briefly explain the motivation for developing such a theory (Kim–Yu’s construction of types of p-adic groups) and present the main geometric results on the cohomology of Weil–Heisenberg Deligne–Lusztig varieties. If time permits, I will put the discussion in a more general framework of the geometric representation theory of Jacobi groups (including Hecke categories, character sheaves, ...). This is a joint work with Charlotte Chan and Tasho Kaletha.

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Oct 14

• Speaker: Huajie Li 李华杰 (Tsinghua University 清华大学)
• Title: A relative trace formula for symmetric spaces: the case of Guo–Jacquet
• In order to generalise a famous theorem of Waldspurger on toric periods to higher ranks, Guo–Jacquet proposed a comparison of relative trace formulae for the symmetric space $GL(2n)/GL(n)\times GL(n)$ and its inner twists. In a recent joint work with Pierre-Henri Chaudouard, we established such a trace formula by a variant of Arthur's truncation. We shall explain its construction in this talk, with emphasis on its distinction from other known relative trace formulae in the literature.

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Oct 21

• Speaker: Zhongyipan Lin 林中一攀 (Tongji University 同济大学)
• Title: Explicit polynomial presentations of the reduced Emerton–Gee stacks
• In this talk, I will introduce my program that seeks to (efficiently) compute the reduced Emerton–Gee stacks in non-generic and high dimension situations. I will explain its arithmetic implications such as a speculative Herzig-type Serre weight recipe for non-semisimple, non-generic residual Galois representations and a speculative classification of weight entailment phenomenon. This talk is based on my recent preprint arXiv:2608.01567 (the "twisted" Borel case) and the joint work in progress with Min Yu (the reductive case). The resolved twisted Borel cases already imply the existence of crystalline lifts and the qualitative Breuil–Mezard conjecture for most reductive groups (without assumptions on the residual Galois representation). To orient the audience, I will start with an exposition of the precursor of the Emerton–Gee stacks –– the moduli of potentially Barsotti–Tate rank 2 Breuil–Kisin modules with tame descent data, and explain how it acquires (twisted) Springer–Schubert geometry. Then I will analyze the non-generic geometry by introducing a mod p (p=l) version of Weil–Deligne representations.

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Oct 28

• Speaker: Xenia Dimitrakopoulou (Aix-Marseille Université)
• Title: TBD

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Nov 11

• Speaker: Lucas Gerth (Centre National de la Recherche Scientifique)
• Title: TBD

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Nov 18

• Speaker: Andrew Graham (University of Oxford)
• Title: TBD

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Nov 25

• Speaker: Wen-Wei Li 李文威 (Peking University 北京大学)
• Title: TBD

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Dec 2

• Speaker: Arnaud Vanhaecke (Chinese Academy of Sciences 中国科学院)
• Title: TBD

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Dec 16 (Two talks!)

• Speaker: Volker Heiermann (Aix-Marseille Université)
• Title: TBD

• Speaker: Yujiao Jiang 蒋玉蛟 (Shandong University 山东大学)
• Title: TBD

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Dec 23

• Speaker: Ruishen Zhao 赵瑞屾 (Tsinghua University 清华大学)
• Title: TBD

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Dec 30

• Speaker: TBD (TBD)
• Title: TBD

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Jan 6

• Speaker: Rafael von Känel (Tsinghua University 清华大学)
• Title: TBD

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