* Dates within the next 7 days are marked by a star.
David Adame-Carrillo (opponent prof. Alessandro Giuliani)
PhD thesis defense: "Lattice models and conformal field theory"
* Tuesday 25 February 2025, 13:00, R002/160a R1
Luis Angel Castillo López (Universidad Nacional Autónoma de México)
TBA
* Wednesday 26 February 2025, 10:15, M3 (M234)
Seminar on analysis and geometry
Kostiantyn Tolmachov (Universität Hamburg)
Around the centrality property of character sheaves on a reductive group
* Thursday 27 February 2025, 14:15, M2 (M233)
I will report on two recent papers establishing some geometric and categorical properties of character sheaves. In one, joint with Gonin and Ionov, we give a new proof and an extension to non-unipotent setting of the t-exactness of the composition of Radon and Harish-Chandra transforms for character sheaves. In another, joint with Bezrukavnikov, Ionov and Varshavsky, we show that this can be used to compute the Drinfeld center of the abelian Hecke category attached to the same reductive group.
Algebra & Discrete Mathematics (ADM) Seminar
Timo Takala
TBA
Wednesday 05 March 2025, 10:15, M3 (M234)
Seminar on analysis and geometry
Thomas Karam (University of Oxford)
TBA
Thursday 06 March 2025, 14:15, Zoom
Algebra & Discrete Mathematics (ADM) Seminar
Håkan Hedenmalm (KTH Stockholm)
Conformally invariant Gaussian analytic functions, holomorphic correlations, and operator symbols of contractions (FMS Colloquium)
Thursday 06 March 2025, 16:15,
Further information
The classical Dirichlet space of holomorphic functions on the unit disk is invariant under Möbius transformations, except that it is equipped with a marked point where the functions vanish. Associated with such a Dirichlet space with a marked point, we get a Gaussian analytic function in a canonical fashion. Then, if we take two such Gaussian analytic functions, say with the same marked point at the origin, we consider the holomorphic correlation function of the two. It turns out to be given in terms a contraction on the area-L2 space on the disk. More precisely, we obtain the operator symbol of the contraction. Some contractions on L2 are perhaps more natural than others. For instance, we can consider the multiplication operator associated with a Beltrami coefficient μ. But we can also consider Grunsky operators, which are prominent in the theory of conformal mapping. We obtain a characterization of the operator symbols of Grunsky operators as solutions to a nonlinear wave equation. We also study the average growth of the L2 means of the operator of a general contraction.
Finnish Mathematical Society colloquium
Jinwoo Sung (Chicago)
A quasi-invariant group action on SLE loops
Monday 10 March 2025, 14:15, Y405
Conformal welding is an operation that encodes Jordan curves on the Riemann sphere in terms of circle homeomorphisms. Thus, composition defines a natural group action of circle homeomorphisms on Jordan curves. In this talk, I will discuss a CameronMartin type quasi-invariance result for the SLE loop measure under the right group action by WeilPetersson homeomorphisms. While this result was hinted by Carfagnini and Wang's identification of Loewner energy as the OnsagerMachlup action functional of the SLE loop measure, the group structure of SLE welding has been little understood previously.
Our proof is based on the characterization of the composition operator associated with WeilPetersson circle homeomorphisms using HilbertSchmidt operators and the description of the SLE loop measure in terms of the welding of two independent quantum disks by Ang, Holden, and Sun. This is joint work with Shuo Fan (Tsinghua University and IHES).
Prof. Marcus Greferath (University College Dublin/Aalto)
Some old and new ideas on noiseless and noisy group testing
Wednesday 12 March 2025, 16:15, M3 (M234)
Group Testing is an area in information and communication sciences that is as well-established as Coding Theory and Cryptography. The author of this talk stumbled over this amazingly interesting topic during the recent COVID-19 pandemic and came to the moderately surprising observation that (non-adaptive) group testing in both the noiseless and the noisy (=error-correcting) case, may be considered as coding theory over the Boolean semi-field (1+1=1). Following this path, he discovered new and re-discovered known results of the theory that now allow for a presentation in a new skin. This talk will delve into the topic and show how Noiseless and Noisy Group Testing can be connected to Partially Ordered Sets, Residuation, Partial Linear Spaces, Configurations, Barbilian Spaces, and Block Designs, which gives raise to further applications of Finite Geometry and Order Theory.
ANTA Seminar / Hollanti et al.
Tuomas Kelomäki (Aalto)
TBA
Friday 21 March 2025, 10:15, M3 (M234)
Nageswari Shanmugalingam (University of Cincinnati)
TBA
Wednesday 26 March 2025, 10:15, M3 (M234)
Seminar on analysis and geometry
Estibalitz Durand Cartagena (UNED, Madrid)
TBA
Wednesday 02 April 2025, 10:15, M3 (M234)
Seminar on analysis and geometry
Hana Ephremidze (Universität Bonn)
TBA
Thursday 03 April 2025, 14:15, M2 (M233)
Algebra & Discrete Mathematics (ADM) Seminar
Yoh Tanimoto (University of Rome Tor Vergata)
TBA
Tuesday 08 April 2025, 10:15, M3 (M234)
Jiasheng Lin (Institut de Mathématiques de Jussieu-Paris Rive Gauche)
TBA
Tuesday 15 April 2025, 10:15, M3 (M234)
Aleksis Koski
TBA
Wednesday 16 April 2025, 10:15, M3 (M234)
Seminar on analysis and geometry
Aapo Pulkkinen
TBA
Wednesday 07 May 2025, 10:15, M3 (M234)
Seminar on analysis and geometry
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