Upcoming Events
- July 6 – 8, 2026 (WIAS-ESH)
- Workshop/Konferenz: Spreading Dynamics in Random Environment
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin
- Wednesday, 08.07.2026, 10:00 (WIAS-HVP-3.13)
- Forschungsseminar Mathematische Statistik
Prof. Dr. Alexandra Carpentier, Universität Potsdam:
Computational lower bounds in clustering and ranking
more ... Location
Weierstraß-Institut, Hausvogteiplatz 11A, 10117 Berlin, 3. Etage, Raum: 3.13
Abstract
In this talk, we will speak about computational lower bounds. After an extended general introduction that presents these tools, and we will focus more particularly on the problem of clustering.
Further Informations
Dieser Vortrag findet auch via Zoom statt: https://hu-berlin.zoom-x.de/j/65177102181?pwd=nUMtJOkzDx8xyWzPFezeHh0NEIQUv3.1, Meeting-ID 651 7710 2181, Kenncode: 536200
Host
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Thursday, 09.07.2026, 14:00 (WIAS-ESH)
- Seminar Numerische Mathematik
Tim van Beeck, Georg-August-Universität Göttingen:
High-order surface flow discretizations via discrete Helmholtz--Hodge decompositions
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstract
We present a discretization of incompressible flows on surfaces of arbitrary topology that avoids a saddle-point formulation. The method is based on a discrete Helmholtz--Hodge decomposition of the divergence-free subspace of H(div)-conforming Brezzi--Douglas--Marini (BDM) finite elements into rotated gradients of a continuous streamfunction space and a finite-dimensional space of discrete harmonic fields whose dimension equals the first Betti number of the surface. This eliminates the pressure and the saddle-point structure while ensuring exact tangentiality, pointwise divergence-freeness, and pressure-robustness. We report numerical experiments for the unsteady surface Navier--Stokes equations on topologically non-trivial surfaces.
Host
WIAS Berlin
- Monday, 13.07.2026, 11:30 (WIAS-406)
- Seminar Interacting Random Systems
Vicente Lenz, TU Delft:
Metastability for the 2-pattern Hopfield model and general product chains
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstract
The Hopfield model is a mean-field spin system designed to store a set of patterns as ground states of its Hamiltonian, providing a simple mathematical model of associative memory. At low temperature, the associated Glauber- Metropolis dynamics is metastable: started near a stored pattern, the system remains in its vicinity for an exponentially long time before an abrupt transition towards another pattern. In this talk I discuss the metastable behavior of the model with two stored patterns. After a brief introduction to the potential-theoretic approach to metastability-capacities, equilibrium potentials, and the variational principles that connect them to metastable transition times - I show how the decomposition of the spin sites into the sets where the two patterns agree and disagree reduces the dynamics, via an exact lumping, to a product of two Curie?Weiss-type chains. We will show how this tensorization structure allows metastability to be propagated from the component chains to the full model capacities of the product chain are controlled by those of its marginals, and one obtains sharp Eyring-Kramers-type estimates for the transition times between the stored patterns. Based on ongoing work with Elena Pulvirenti and Martin Slowik.
Further Informations
Seminar Interactin Random Systems
Host
WIAS Berlin
- Tuesday, 14.07.2026, 10:00 (WIAS-ESH)
- Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations / Mathematical Optimization
Alexey Izmailov, Brown University, USA:
A Proximal Discontinuous Galerkin Method for Total Bounded Variation Based Image Denoising
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstract
Image denoising is classically posed as a variational problem. A clean image is recovered as the minimizer of an energy that balances fidelity to the noisy data against a regularization term, which makes the problem of separating signal from noise well-posed. Total bounded variation (BV) is known to preserve sharp edges in the original image more effectively than other regularizers, but requires the solution of a problem posed over a non-reflexive Banach space. In 2004, Hintermüller and Kunisch showed that the Fenchel predual to the BV-regularized denoising problem is a bilaterally-constrained quadratic optimization problem posed over the Hilbert space H(div). The proximal Galerkin (PG) method has recently been developed for the numerical solution of variational inequalities with pointwise inequality constraints in infinite-dimensional function spaces using finite elements. We introduce and analyze a proximal interior penalty discontinuous Galerkin (PIPDG) method for the Hintermüller-Kunisch problem, constituting the first application of the PG framework to problems posed directly over H(div). We establish well-posedness of the discrete subproblems, energy dissipation, and a priori error estimates. Numerical experiments on smooth manufactured solutions, an analytical benchmark with a discontinuous datum, and real image denoising confirm the predicted convergence rates. The two-fold saddle-point system derived for this problem is an example of a more general structure encountered while extending PG to state-constrained optimal control and vector Laplacian obstacle problems. On-going work for these problems will also be briefly showcased. This talk is based on joint work with Brendan Keith and Pratyush Potu (Brown University).
Further Informations
Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations
Host
WIAS Berlin
- Tuesday, 14.07.2026, 14:14 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Assoc. Prof. Eris Runa, San Grasso Science Institute, Italien:
Pattern formation and symmetry breaking for a family of functionals and their intrinsic nonlocal curvature
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstract
In this talk, we will introduce a rigorous approach to the study of the symmetry breaking and pattern formation phenomenon for isotropic functionals with local/nonlocal interactions in competition. More precisely, we consider a general class of nonlocal variational problems in general dimension d, in which an isotropic surface term favouring pure phases competes with an isotropic nonlocal term with power law kernel favouring alternation between different phases. Close to the critical regime in which the two terms are of the same order, we give a rigorous proof of the conjectured structure of global minimizers, in the shape of domains with flat boundary (e.g. stripes or lamellae). In order to show such structure we will use nonlocal curvatures which appear naturally in these types of problems. This work is in collaboration with S. Daneri.
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Wednesday, 15.07.2026, 10:00 (WIAS-ESH)
- Forschungsseminar Mathematische Statistik
Dr. Sascha Gaudlitz, Humboldt-Universität zu Berlin:
A Bernstein-von Mises Theorem for indirect measurement models with nonlinear unbounded forward operators
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Dieser Vortrag findet auch via Zoom statt: https://hu-berlin.zoom-x.de/j/65177102181?pwd=nUMtJOkzDx8xyWzPFezeHh0NEIQUv3.1, Meeting-ID 651 7710 2181, Kenncode: 536200
Host
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Wednesday, 15.07.2026, 11:30 (WIAS-406)
- Seminar Interacting Random Systems
Orion Mauduit, ENS Paris-Saclay:
tba
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstract
tba
Further Informations
Seminar Interactin Random Systems
Host
WIAS Berlin
- Wednesday, 15.07.2026, 14:15 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Jun.-Prof. Dr. Christina Lienstromberg, Universität Stuttgart:
Dynamics of a 3D rimming flow
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Wednesday, 29.07.2026, 14:15 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Ass. Prof. Quoc Bao Tang, Universität Graz, Österreich:
Global existence and large time behaviour of nonlinear reaction-diffusion systems
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- September 7 – 11, 2026 (HUB main building)
- Workshop/Konferenz: 17th International Conference on Free Boundary Problems: Theory and Applications 2026
more ... Location
Humboldt Universität zu Berlin, Unter den Linden 6, 10117 Berlin
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- November 3 – 6, 2026 (WIAS-ESH)
- Workshop/Konferenz: Stochastic processes with reinforcement
more ... Location
Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin