Veranstaltungen
- Mittwoch, 17.12.2025, 10:00 Uhr (WIAS-HVP-3.13)
- Forschungsseminar Mathematische Statistik
Dr. Cesare Miglioli, University of Pittsburgh, USA:
Incomplete U-statistics of equireplicate designs: Berry-Esseen bound and efficient construction
mehr ... Veranstaltungsort
Weierstraß-Institut, Hausvogteiplatz 11A, 10117 Berlin, 3. Etage, Raum: 3.13
Abstrakt
U-statistics are a fundamental class of estimators that generalize the sample mean and underpin much of nonparametric statistics. Although extensively studied in both statistics and probability, key challen- ges remain. These include their inherently high computational cost addressed partly through incomplete U-statistics and their non-standard asymptotic behavior in the degenerate case, which typically requires resampling methods for hypothesis testing. This talk presents a novel perspective on U-statistics, groun- ded in hypergraph theory and combinatorial designs. Our approach bypasses the traditional Hoe?ding decomposition, which is the the main analytical tool in this literature but is highly sensitive to degeneracy. By fully characterizing the dependence structure of a U-statistic, we derive a new Berry-Esseen bound that applies to all incomplete U-statistics based on deterministic designs, yielding conditions under which Gaussian limiting distributions can be established even in the degenerate case and when the order diverges. Moreover, we introduce e cient algorithms to construct incomplete U-statistics of equireplicate designs, a subclass of deterministic designs that, in certain cases, enable to achieve minimum variance. To illustrate the power of this novel framework, we apply it to kernel-based testing, focusing on the widely used two- sample Maximum Mean Discrepancy (MMD) test. Our approach leads to a permutation-free variant of the MMD test that delivers substantial computational gains while retaining statistical validity.
Weitere Informationen
Dieser Vortrag findet hybrid statt. Die Teilnahme per Zoom ist über den (neuen!) Link:
https://hu-berlin.zoom-x.de/j/64809417303?pwd=iLT5xbdDZspAcUCuLrwNnaN90ZQBpj.1
Meeting-ID: 648 0941 7303
Passwort: 258449
Veranstalter
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Mittwoch, 17.12.2025, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Sebastian Hensel, Universität Leipzig:
A weak-strong uniqueness principle for the Mullins--Sekerka equation
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
We establish a weak-strong uniqueness principle for the two-phase Mullins--Sekerka equation in ambient dimension d = 2 and 3: As long as a classical solution to the evolution problem exists, any weak De Giorgi type varifold solution (see for this notion the recent work with Stinson, Arch. Ration. Mech. Anal. 248, 8, 2024) must coincide with it. In particular, in the absence of topology changes such weak solutions do not introduce a mechanism for (unphysical) non-uniqueness. We also derive a stability estimate with respect to changes in the data. I will explain our method which is based on the notion of relative entropies for interface evolution problems, a reduction argument to a perturbative setting, and a stability analysis in this perturbative regime relying crucially on the gradient flow structure of the Mullins--Sekerka equation. This is joint work with Julian Fischer, Tim Laux and Theresa M. Simon.
Weitere Informationen
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- 12. – 13. Januar 2026 (WIAS-ESH)
- Workshop/Konferenz: Recent Trends in Coupled Network Systems
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin
- Mittwoch, 14.01.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Marcel Ortgiese, University of Bath:
tba
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
tba
Weitere Informationen
Seminar Interactin Random Systems
Veranstalter
WIAS Berlin
- Donnerstag, 15.01.2026, 14:00 Uhr (WIAS-405-406)
- Seminar Numerische Mathematik
Prof. Petr Knobloch, Charles University, Tschechische Republik:
Computation of stabilization parameters using machine learning
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstrakt
For various types of partial differential equations, standard finite element discretizations are often unstable, which can be cured by adding suitable stabilization terms. Typically, these terms contain user-chosen parameters whose optimal choice is usually not known but which considerably influence the quality of the approximate solution. In this talk, we will consider stabilized methods for steady convection-diffusion equations. A typical example is the streamline upwind Petrov-Galerkin (SUPG) method. It is possible to compute the stabilization parameters a posteriori in an adaptive way by minimizing a target functional characterizing the quality of the approximate solution, however, this functional is often difficult to design. Moreover, the solution of this high-dimensional constrained nonlinear optimization problem is usually very time-consuming. Therefore, we proposed a method based on techniques from machine learning in order to select (nearly) optimal stabilization parameters in a cheap way. The idea is to compute these parameters locally based on properties of the SUPG solution obtained with standard (nonoptimal) parameters. The training phase will use parameters computed by the mentioned minimization approach employing accurate approximate solutions which can be obtained using nonlinear (and hence again costly) approaches. We will report our first experiences with this strategy. This is the joint work with Manoj Prakash (Charles University, Prague).
Weitere Informationen
Seminar Numerical Mathematics
Veranstalter
WIAS Berlin
- Mittwoch, 21.01.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Yannic Steenbeck, TU Braunschweig:
tba
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
tba
Weitere Informationen
Seminar Interactin Random Systems
Veranstalter
WIAS Berlin
- Mittwoch, 21.01.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
PD Dr. Olaf Klein, WIAS Berlin:
Uncertainty quantification for a model for a magnetostrictive material involving a hysteresis operator
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Mittwoch, 28.01.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Anastasija Pešić, WIAS Berlin:
Curvature-driven pattern formation in biomembranes: A gradient flow approach
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Mittwoch, 11.02.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Elias Zimmermann, Universität Leipzig:
tba
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
tba
Weitere Informationen
Seminar Interactin Random Systems
Veranstalter
WIAS Berlin
- 2. – 4. März 2026 (IHP)
- Workshop/Konferenz: Leibniz MMS Days 2026
mehr ... Veranstaltungsort
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
Veranstalter
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
WIAS Berlin
- 1. – 5. Juni 2026 (WIAS-ESH)
- Workshop/Konferenz: ESGI 194 - The Berlin Study Group with Industry
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin
- 6. – 8. Juli 2026 (WIAS-ESH)
- Workshop/Konferenz: Spreading Dynamics in Random Environment
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin