Tue, 10 Nov 2026
14:00
14:00
L6
Tue, 03 Nov 2026
14:00
14:00
L6
Tue, 27 Oct 2026
14:00
14:00
L6
Clasps in sl_3 webs at roots of unity
Charles Senécal
(DAMTP, University of Cambridge)
Abstract
The sl_3 web category is a combinatorial model for the representation theory of the quantum group U_q(sl_3). We study the category from the cellular point of view, exploiting diagrammatic methods and light-ladder bases to compute branching rules, homomorphisms, and composition factors of cell modules when q is a root of unity. We then apply these results to the study of clasps. In the semisimple case, these higher rank analogues of the Jones—Wenzl idempotents can be constructed using Elias’s recursive triple-clasp expansion. When q is a root of unity, however, their construction is considerably more subtle, and we use the aforementioned results from cellularity to obtain formulas for some of the non-semisimple clasps.
Tue, 20 Oct 2026
14:00
14:00
L6
A nonabelian Fourier transform for p-adic groups
Albert Lopez Bruch
(Kings’ College London)
Abstract
Under the Local Langlands Correspondence, unipotent representations of a p-adic group admit a natural parametrization in terms of geometric data attached to the dual group. On the other hand, these representations can be described explicitly using the theory of unipotent representations of finite groups of Lie type, developed by Deligne and Lusztig.
A central ingredient in this theory is Lusztig’s nonabelian Fourier transform, a key element in the construction of irreducible characters of finite reductive groups. In this talk, I will explain this algebraic construction and the connection between representations of p-adic groups to those of finite groups of Lie type. Finally, I will discuss recent efforts to construct an analogue of the nonabelian Fourier transform in the p-adic setting, and summarize the progress achieved so far.
Tue, 13 Oct 2026
14:00
14:00
L6
Analytic arithmetic deformation theory
Kobi Kremnitzer
(Mathematical Institute University of Oxford)
Abstract
I will describe a method that deforms analytic cycles to algebraic cycles. This will be done using global derived analytic geometry and analytic (Efimov) K-theory. I will conjecture how this is related to the Tate and Hodge conjectures. If time permits, I will speculate about a global arithmetic site. This is joint work in progress with Federico Bambozzi, Jack Kelly, and Devarshi Mukherjee.
Ordered Ramsey Numbers of Powers of Paths
Girão, A
Janzer, B
Janzer, O
Combinatorica
volume 46
issue 4
27
(29 Jul 2026)
doi:10.1007/s00493-026-00223-0
Tue, 24 Nov 2026
16:00
16:00
L5
Tue, 17 Nov 2026
16:00
16:00
L5