Upcoming Events
- October 8 – 10, 2025 (WIAS-ESH)
- Workshop/Konferenz: Current Research at the Interface of Continuum Physics and Applied Mathematics (in memoriam Wolfgang Dreyer)
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin
- Wednesday, 08.10.2025, 11:30 (WIAS-405-406)
- Seminar Interacting Random Systems
Tejas Iyer, WIAS Berlin:
tba
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Host
WIAS Berlin
- October 15 – 17, 2025 (WIAS-ESH)
- Workshop/Konferenz: Recent Developments in Spatial Interacting Random Systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin
- Wednesday, 15.10.2025, 14:15 (WIAS-Library)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Annalaura Rebucci, MPI für Mathematik in den Naturwissenschaften:
On the De Giorgi--Nash--Moser regularity theory for kinetic hypoelliptic operators
more ... Location
Weierstraß-Institut, Hausvogteiplatz 5-7, 10117 Berlin, R411
Abstract
We present new results that extend the De Giorgi--Nash--Moser theory to a class of hypoelliptic equations naturally arising in kinetic theory. These operators are mathematically characterized by two parts: a diffusion part governed by the (fractional) Laplace operator in some set of variables and a first order operator that contains the directions of missing ellipticity. A key ingredient to prove our results is a Poincaré inequality, which we derive from the construction of suitable trajectories. The trajectories we rely on are quite flexible and allow us to consider equations with an arbitrary number of Hörmander commutators and whose diffusive part is either local (second-order) or nonlocal (fractional order). We later combine the Poincaré inequality with a L2 - L∞ estimate, a Log-transformation and a classical covering argument (Ink--Spots Theorem) to deduce Harnack inequalities and Höllder regularity along the line of De Giorgi method. This talk is based on a series of papers in collaboration with F. Anceschi, H. Dietert, J. Guerand, A. Loher and C. Mouhot.
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Wednesday, 22.10.2025, 11:30 (WIAS-405-406)
- Seminar Interacting Random Systems
Helia Shafigh, WIAS Berlin:
Responsive dormancy of a spatial population among a moving trap
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstract
In this talk, we study a spatial model for dormancy in a random environment via a two-type branching random walk in continuous-time, where individuals switch between dormant and active states depending on the current state of a fluctuating environment (responsive switching). The branching mechanism is governed by the same random environment, which is here taken to be a simple symmetric random walk. We will interpret the presence of this random walk as a trap which attempts to kill the individuals whenever it meets them. The responsive switching between the active and dormant state is defined so that active individuals become dormant only when a trap is present at their location and remain active otherwise. Conversely, dormant individuals can only wake up once the environment becomes trap-free again. We quantify the influence of dormancy on population survival by analyzing the long-time asymptotics of the expected population size. The starting point for our mathematical considerations and proofs is the Parabolic Anderson Model via the Feynman-Kac formula. In particular, we investigate the quantitative role of dormancy by extending the Parabolic Anderson Model to a two-type random walk framework.Joint work with Leo Tyrpak.
Host
WIAS Berlin - Wednesday, 22.10.2025, 14:15 (WIAS-Library)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Annamaria Massimini, Ecole Nationale des Ponts et Chaussées, FR:
Finite volumes for a generalized Poisson--Nernst--Planck system with cross-diffusion
more ... Location
Weierstraß-Institut, Hausvogteiplatz 5-7, 10117 Berlin, R411
Abstract
Modeling concentrated ion mixtures in solvents like water is a complex research area with key applications in biology (e.g., ion transport through protein channels) and electrochemistry (e.g., batteries). In this talk, I will present a finite volume scheme for modeling the diffusion of ions in constrained geometries using a degenerate Poisson--Nernst--Planck system with size exclusion yielding cross-diffusion. The proposed method utilizes a two-point flux approximation and is part of the exponentially fitted scheme framework. The scheme is shown to be thermodynamically consistent, as it ensures the decay of some discrete version of the free energy. Classical numerical analysis results - existence of discrete solution, convergence of the scheme as the grid size and the time step go to 0 - follow. The long-time behavior of the scheme is also investigated, both from a theoretical and numerical point of view. Numerical simulations confirm our findings, but also point out some possibly very slow convergence towards equilibrium of the system under consideration. This is a joint work with Clément Cànces and Maxime Herda.
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Wednesday, 29.10.2025, 11:30 (WIAS-405-406)
- Seminar Interacting Random Systems
Hanna Stange, Universität Münster:
tba
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Host
WIAS Berlin
- November 4 – 6, 2025 (WIAS-ESH)
- Workshop/Konferenz: Mathematics for Smart Energy
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin
- Wednesday, 19.11.2025, 14:15 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Lutz Recke, Humboldt-Universität zu Berlin:
An H-convergence-based implicit function theorem and homogenization of nonlinear non-smooth elliptic systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- January 12 – 13, 2026 (WIAS-ESH)
- Workshop/Konferenz: Recent Trends in Coupled Network Systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin
- March 2 – 4, 2026 (IHP)
- Workshop/Konferenz: Leibniz MMS Days 2026
more ... Location
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
Host
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
WIAS Berlin
- June 1 – 5, 2026 (WIAS-ESH)
- Workshop/Konferenz: ESGI 194 - The Berlin Study Group with Industry
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin