Veranstaltungen
- Dienstag, 12.05.2026, 15:00 Uhr (WIAS-406)
- Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Dr. Pavel Dvurechensky, WIAS Berlin:
On global rates for semismooth Newton method
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
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Dieser Vortrag findet auch via Zoom statt: https://wias-berlin-de.zoom-x.de/j/69982487566
Veranstalter
WIAS Berlin
- Mittwoch, 13.05.2026, 10:00 Uhr (WIAS-ESH)
- Forschungsseminar Mathematische Statistik
Prof. Dr. Holger Dette, Ruhr-Universität Bochum:
Multiple change point detection in functional data with applications to biomechanical fatigue data
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
Injuries to the lower extremity joints are often debilitating, particularly for professional athletes. Understanding the onset of stressful conditions on these joints is therefore important in order to ensure prevention of injuries as well as individualised training for enhanced athletic performance. We study the biomechanical joint angles from the hip, knee and ankle for runners who are experiencing fatigue. The data is cyclic in nature and densely collected by body worn sensors, which makes it ideal to work with in the functional data analysis (FDA) framework. We develop a new method for multiple change point detection for functional data, which improves the state of the art with respect to at least two novel aspects. First, the curves are compared with respect to their maximum absolute deviation, which leads to a better interpretation of local changes in the functional data compared to classical $L^2$-approaches. Secondly, as slight aberrations are to be often expected in a human movement data, our method will not detect arbitrarily small changes but hunts for relevant changes, where maximum absolute deviation between the curves exceeds a specified threshold, say $Delta >0$. We recover multiple changes in a long functional time series of biomechanical knee angle data, which are larger than the desired threshold $Delta$, allowing us to identify changes purely due to fatigue. In this work, we analyse data from both controlled indoor as well as from an uncontrolled outdoor (marathon) setting.
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Dieser Vortrag findet auch via Zoom statt: https://wias-berlin-de.zoom-x.de/j/69982487566
Veranstalter
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Mittwoch, 13.05.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Quan Shi, AMSS Chinese Academy of Sciences:
Two phase transitions for catalytic branching Markov chains
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
Consider a continuous-time branching Markov chain $(Z_t,tge 0)$ on a locally finite graph $G$ rooted at $mathbfo$. Each particle moves according to an irreducible Markov process $xi$ and branches at a rate that depends on their location: the branching rate is $lambda_rtge 0$ at the root and $lambdage 0$ elsewhere. The offspring distribution is supercritical with mean $m>1$, has no extinction and finite second moment. We characterize the recurrence/transience phase transition for this catalytic branching Markov chain. Furthermore, under suitable assumptions we prove a second phase transition concerning the asymptotic behaviour of the relative empirical density, $(Z_t(G))^-1 Z_t$, where $Z_t$ is the empirical measure of the particles and $Z_t(G)$ is the total population size. If $(m-1)(lambda_0-lambda)> gamma_esc$, where $gamma_esc$ is the escape probability that $xi$ never returns to the root, then $(Z_t(G))^-1 Z_t$ converges almost surely to a deterministic probability measure. If $(m-1)(lambda_0-lambda)in (0, gamma_esc]$, then $(Z_t(G))^-1 Z_t$ converges almost surely to zero. When the graph is the integer lattice $G=mathbbZ^d$ and $xi$ is the simple random walk, our results confirm several conjectures of Mailler and Schapira [Ann. Appl. Probab. 2026], which studied this model via a different approach. Based on a joint work in progress with Xinxin Chen (Bejing Normal Unversity), Nina Gantert (Technical University of Munich) and Haojie Hou (Beijing Institute of Technology).
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Seminar Interacting Random Systems (Hybrid Event)
Veranstalter
WIAS Berlin
- Mittwoch, 13.05.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Marco Inversi, MPI, Leipzig:
Energy dissipation and shocks in ideal fluid systems
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
In an ideal density dependent fluid system, is the total energy dissipated on shock type discontinuities?
To this end, we study the local energy balance for weak solutions to the isentropic compressible Euler system and derive fine properties of the defect measure, that describes the (possible) loss of the total energy. This is done by a careful analysis of the small scale properties of the solutions at the shock discontinuity. By means of the same technique, we also consider the inhomogeneous incompressible case, and, comparing the result, we confirm the general principle that the accumulation of the total energy on cxdimension one singular structures is a feature that distinguishes compressible and incompressible models.
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Berliner Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Mittwoch, 20.05.2026, 10:00 Uhr (WIAS-ESH)
- Forschungsseminar Mathematische Statistik
Prof. Dr. Johannes Schmidt-Hieber, University of Twente, Niederlande:
A new neural network architecture for learning convex functions
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
For small covariate dimension, shape constrained inference is a well-established topic within nonparametric statistics. For large covariate dimensions, one naturally wants to introduce machine learning based methods. Input convex neural networks (ICNNs) were designed as a network architecture to learn convex functions. In this talk, we introduce Hyper Input Convex Neural Networks (HyCNNs). HyCNNs combine the principles of Maxout networks with ICNNs to create a neural network that is always convex in the input, theoretically capable of leveraging depth, and performs reliable when trained at scale compared to ICNNs. Concretely, we prove that HyCNNs require exponentially fewer parameters than ICNNs to approximate quadratic functions up to a given precision. Throughout a series of synthetic experiments, we demonstrate that HyCNNs outperform existing ICNNs and MLPs in terms of predictive performance for convex regression and interpolation tasks. WWe further apply HyCNNs to learn high-dimensional optimal transport maps for synthetic examples and for single-cell RNA sequencing data, where they oftentimes outperform ICNN-based neural optimal transport methods and other baselines across a wide range of settings. For more details, see arxiv.org/pdf/2604.26942. This is joint work with Shayan Hundrieser and Insung Kong
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Dieser Vortrag findet auch via Zoom statt: https://wias-berlin-de.zoom-x.de/j/69982487566
Veranstalter
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Mittwoch, 20.05.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Julian Kern, FU Berlin:
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 Interacting Random Systems (Hybrid Event)
Veranstalter
WIAS Berlin
- Mittwoch, 20.05.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Prof. Dr. Riccarda Rossi, University of Brescia, Italien:
BV curves of measures
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
Representation results for absolutely continuous curves with values in the Wasserstein space of Borel probability measures in ℝd with finite p-moment, p > 1, provide a crucial tool to study evolutionary PDEs in a measure-theoretic setting. They are strictly related to the superposition principle for measure-valued solutions to the continuity equation. This talk revolves around the extension of these results to the case p = 1, and to curves that are only of bounded variation in time. Based on a joint collaboration with Stefano Almi (Napoli) and Giuseppe Savaré (Milano).
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Berliner Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Donnerstag, 21.05.2026, 10:30 Uhr (WIAS-Library)
- Software and Data Seminar
Laura Prieto Saavedra, WIAS Berlin:
Introduction to ParaView
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Weierstraß-Institut, Hausvogteiplatz 5-7, 10117 Berlin, R411
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Seminar Software and Data
Veranstalter
WIAS Berlin
- Mittwoch, 27.05.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
David Dereudre, University of Lille:
Rigidity of Riesz gases
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
In this talk, we will survey the rigidity of Riesz gases, which are equilibrium states (or Gibbs measures) in $mathbbR^d$ of continuum particle systems subjected to the Riesz potential. Here, rigidity refers to hyperuniformity, number rigidity, or symmetry breaking (such as crystallization or cyclic factor property). Several results will be presented, along with a number of conjectures.
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Seminar Interactin Random Systems
Veranstalter
WIAS Berlin
- Mittwoch, 27.05.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Prof. Dr. Tomáš Roubíček, Czech Academy of Sciences, Tschechische Republik:
The Stefan problem with a phase transition between visco-elastic fluids and finitely-strained solids
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
The compressible fluid-solid interaction (FSI) with a thermomechanical phase transition is formulated at large strains in the Eulerian frame. The Jeffreys (also called anti-Zener) rheology in the deviatoric part with an additional viscosity is used. The main philosophy for the mechanical solid-liquid transition is that the viscous (or viscoplastic) response depends on temperature and may completely degenerate towards a viscoelastic fluid during thawing, which then allows for free flow of the fluid and its freezing in a new configuration and possibly again subsequent melting towards the fluid unlimitedly repeating such cycles. The classical Stefan problem related with the latent heat of the 1st-order (i.e. here thawing-freezing) phase transition is augmented by involving kinetic overheating and undercooling. The (sketched) analysis by a time discretization with a suitable truncation is applied to a higher-gradient modification of the original problem, i.e. involving the concept of multipolar nonsimple material. Some enhancements of the basic model as phase-field fracture in the solid phase or a diffusant dependency (like a salinity variation within the sea water/ice transition or a nickel content variation within the Earth inner/outer core transition) will be outlined, too.
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Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Donnerstag, 28.05.2026, 10:30 Uhr (WIAS-Library)
- Software and Data Seminar
Nikolas Tapia:
Introduction to Lean
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Weierstraß-Institut, Hausvogteiplatz 5-7, 10117 Berlin, R411
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Software and Data Seminar
Veranstalter
WIAS Berlin
- 1. – 5. Juni 2026 (WIAS-ESH)
- Workshop/Konferenz: ESGI 194 - The Berlin Study Group with Industry
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin
- Donnerstag, 11.06.2026, 14:00 Uhr (WIAS-ESH)
- Seminar Materialmodellierung
Prof. Dr. Dieter Bothe, Technische Universität Darmstadt:
Sharp interface modelling fundamentals for two-phase fluid systems
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Weierstraß-Institut, Anton-Wilhelm-Amo-Str. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
The sharp interface framework enables a thermodynamically consistent description of two-phase fluid systems, representing interfaces as moving hypersurfaces separating bulk phases. Starting from classical balance laws for mass and momentum, the local kinematics of two-phase flows with phase change and interfacial slip is addressed. Since the associated kinematic differential equation may exhibit non-uniqueness, the notion of co-moving sets must first be consolidated in order to establish a two-phase Reynolds transport theorem. On this basis, balance laws and jump conditions for multicomponent two-phase fluid systems are formulated, consistently coupling bulk and interfacial dynamics. Building on the Gibbsian concept of interfaces as autonomous lower-dimensional thermodynamic subsystems, extensions with interfacial mass are introduced, enabling full thermodynamic coupling with the adjacent bulk phases and thereby promoting the interface to an interphase. Finally, extensions to multi-velocity and multi-temperature formulations are outlined.
Veranstalter
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
Veranstalter
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
