Speaker: Nicolás Arancibia Robert
Room: MS377
Time: Aug 20 11:00am-12:00pm.
Abstract: Relying on work of Kashiwara-Schapira and Schmid-Vilonen, we describe the behaviour of characteristic cycles with respect to the operation of geometric induction, the geometric counterpart of taking parabolic or cohomological induction in representation theory. By doing this, we are able to describe the characteristic cycle associated to an induced representation in terms of the characteristic cycle of the representation being induced. As a consequence, we prove that the cohomology packets defined by Adams and Johnson in [AJ87] are micro- packets, that is to say that the cohomological constructions of [AJ87] are particular cases of the sheaf-theoretic ones in [ABV92]. It is important to mention that the equality between the packets defined in [AJ87] and the ones in [ABV92] is known for the experts, but to my knowledge no proof of it can be found in the literature.
Event Date: Tuesday, August 20, 2019 - 11:00 to 12:00
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Participants:
Clifton Cunningham, University of Calgary
Sarah Dijols, Tsinghua University
Andrew Fiori, University of Lethbridge
Ahmed Moussaoui, Université Versailles Saint Quentin
Kam-Fai Tam (Geo), Radboud University Nijmegen
Bin Xu, Yau Mathematical Sciences Center, Tsinghua University
Qing Zhang, PIMS Postdoctoral Scholar, University of Calgary
Geoff Vooys, Graduate Student, University of Calgary
http://www.birs.ca/events/2019/focussed-research-groups/19frg277
Event Date: Sunday, July 21, 2019 - 09:00 to Sunday, July 28, 2019 - 17:00
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Tian An Wong (UBC)
Abstract: In this talk, I will outline the basic ideas in Langlands’ Beyond Endoscopy proposal, and the role of summation formulas and the nontempered automorphic spectrum. I will discuss the various approaches of Frenkel-Langlands-Ngô, Altug, and Ngô to the geometric side of the trace formula, and propose an alternate approach beginning on the spectral side instead.
Location: MS 337 + https://zoom.us/j/171589529
Event Date: Tuesday, May 14, 2019 - 11:00 to 12:30
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Venue: Representation Theory Seminar at University of Alberta
https://sites.ualberta.ca/~kkoziol/sem/NTRT.html
Title: The geometry of Arthur packets
Abstract: This talk uses two examples to show how Arthur parameters determine a category of equivariant perverse sheaves and how the microlocal perspective on this category reveals the Arthur packet attached to the Arthur parameter. The full picture is explained in Arthur packets for p-adic groups by way of microlocal vanishing cycles, with examples, joint with Andrew Fiori, Ahmed Moussaoui, James Mracek and Bin Xu, to appear in Memoirs of the American Mathematical Society. The talk includes some remarks on an emerging categorical local Langlands correspondence.
Event Date: Friday, March 22, 2019 - 14:30 to 16:00
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On the compactification of mini-Vogan varieties V and the restriction functor D_P(G/P) --> D_H(V).
Clifton and Qing in Calgary, Geo in Radboud and Andrew in Lethbridge
Location: Zoom
Event Date: Thursday, March 21, 2019 - 07:00 to 09:00
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Speakers: James Steele and André de Waal
We continue our study of the quiver category A_n and the four functors
J^* : A_n --> A_0,
J_* : A_0 --> A_n,
J_! : A_0 --> A_n and
J_{!*} : A_0 --> A_n.
The goal of the talk is to prove Propositions 3.3, 3.5 and 3.6 of Section 3.2 of Tom Braden's thesis.
Event Date: Wednesday, March 20, 2019 - 09:00 to 10:00
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Speaker: Qing Zhang
Qing and Clifton have now computed all ABV-packets for all unipotent Arthur parameters of the exceptional group G(2). The results are summarized in this talk.
Event Date: Wednesday, March 13, 2019 - 09:00
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Speaker: Geoff Vooys
In this talk we will introduce the Bernstein Decomposition and describe the Bernstein Centre of the category of smooth representations of the F-rational points of a p-adic group G. We will then describe how to realize the Bernstein Centre as a ring of sections of a variety, and, time permitting, use this to explain the parametrization of the Bernstein Decomposition.
Event Date: Wednesday, February 6, 2019 - 09:00 to 10:30
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Nicole will update us on her progress toward calculating the microlocal vanishing cycles of the Kashiwara-Saito singularity.
Event Date: Wednesday, January 23, 2019 - 09:00 to 10:00
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Clifton will make a small correction to the geometric multiplicity matrix for the admissible representations of G(2) with “subregular unipotent” infinitesimal parameter.
Qing will explain that he’s found all the admissible representations and standard modules of G(2) with “subregular unipotent” infinitesimal parameter and that the multiplicity matrix matches the geometric calculation. This concludes the proof of the Kazhdan-Lusztig conjecture (as it appears in the Voganish book) for the subregular unipotent infinitesimal parameter of G(2).
Event Date: Wednesday, January 16, 2019 - 09:00 to 10:30
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