Dates: Wednesday, April 29, 2026 - July 08, 2026
Organizers Hausdorff Colloquium: Barbara Verfürth, Herbert Koch and Johannes Alt
Organizers HSM Colloquium: Magdalena Balcerak Jackson, Jilly Kevo, Tingxiang Zou
Venue: Lipschitzsaal, Mathezentrum, Endenicher Allee 60, 53115 Bonn
Date
Hausdorff Tea
Hausdorff Colloquium
HSM Colloquium
29.04.2026
15:00
06.05.2026
Special Event starts at 15:00!
Special Event: International Women in Mathematics Day
15:00 Tatjana Tchumatchenko (University of Bonn)
"TBA"
16:00 Math Pub Quiz about female mathematicians with drinks and snacks
03.06.2026
15:00
17.06.2026
15:00
15:15
TBA
01.07.2026
15:00
15:15
Anna Wienhard (MPI-MIS Leipzig)
"TBA"
08.07.2026
15:00
15:15
TBA
Cristiana De Filippis (University of Parma): "Surfing Regularity on Nonlinear Potentials"
The representation formula for the Poisson equation gives an explicit expression of solutions in terms of the data, yielding zero- and first-order pointwise bounds via convolution with appropriate Riesz potentials. The mapping properties of these potentials provide sharp regularity transfer from data to solutions, giving a complete description of the regularity features of solutions. I will outline key aspects of nonlinear potential theory that reproduce this behavior for nonlinear elliptic PDEs, where representation formulae are unavailable, and trace their regularity theory back to that of the Poisson equation up to the C^{1} level. I will then present a novel potential-theoretic approach, altering a century old paradigm in nonlinear regularity theory, that resolves the longstanding problem of the validity of Schauder theory in nonuniformly elliptic PDEs.
Justin Salez (Université Paris Dauphine): "An invitation to the cutoff phenomenon"
The cutoff phenomenon is an abrupt transition from out of equilibrium to equilibrium undergone by certain Markov processes in the limit where the size of the state space tends to infinity. Discovered four decades ago in the context of card shuffling, this surprising phenomenon has since then been observed in a variety of models, from random walks on groups or complex networks to Glauber dynamics for high-temperature spin systems. It is now believed to be universal among fast-mixing high-dimensional processes. Yet, current proofs are heavily model-dependent, and identifying the general conditions that trigger a cutoff remains one of the biggest challenges in the quantitative analysis of finite Markov chains. In this talk, I will provide a self-contained introduction to this fascinating question, and then describe a recent partial answer based on entropy and curvature.