Veranstaltungen
- Donnerstag, 02.07.2026, 14:00 Uhr (WIAS-Library)
- Software and Data Seminar
Patrick Jaap, WIAS Berlin:
Shipping your computer over the internet: What are Docker & Podman containers?
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Weierstraß-Institut, Hausvogteiplatz 5-7, 10117 Berlin, R411
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Seminar Software and Data
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WIAS Berlin
- 6. – 8. Juli 2026 (WIAS-ESH)
- Workshop/Konferenz: Spreading Dynamics in Random Environment
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
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WIAS Berlin
- Donnerstag, 09.07.2026, 14:00 Uhr (WIAS-ESH)
- Seminar Numerische Mathematik
Tim van Beeck, Georg-August-Universität Göttingen:
High-order surface flow discretizations via discrete Helmholtz--Hodge decompositions
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
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.
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WIAS Berlin
- Montag, 13.07.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Vicente Lenz, TU Delft:
Metastability for the 2-pattern Hopfield model and general product chains
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
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.
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Seminar Interactin Random Systems
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WIAS Berlin
- Dienstag, 14.07.2026, 10:00 Uhr (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
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
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).
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Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations
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WIAS Berlin
- Dienstag, 14.07.2026, 14:14 Uhr (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
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
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.
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Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
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Humboldt-Universität zu Berlin
WIAS Berlin
- Mittwoch, 15.07.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Orion Mauduit, ENS Paris-Saclay:
tba
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
tba
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Seminar Interactin Random Systems
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WIAS Berlin
- Mittwoch, 15.07.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Jun.-Prof. Dr. Christina Lienstromberg, Universität Stuttgart:
Dynamics of a 3D rimming flow
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
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Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Mittwoch, 29.07.2026, 14:15 Uhr (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
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
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Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- 7. – 11. September 2026 (HUB main building)
- Workshop/Konferenz: 17th International Conference on Free Boundary Problems: Theory and Applications 2026
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Humboldt Universität zu Berlin, Unter den Linden 6, 10117 Berlin
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- 3. – 6. November 2026 (WIAS-ESH)
- Workshop/Konferenz: Stochastic processes with reinforcement
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin