Research Seminar RTG 2131
Archive of Talks from Previous Semesters
Summerterm 2021
At Ruhr University Bochum (Online)
Winterterm 2020/21
At TU Dortmund (Online).
Date  Speaker  Title 

02.11.  Holger Rauhut  Structured Random Matrices in Compressive Sensing and Suprema of Chaos Processes 
09.11.  Nina Gantert  Large deviations for lacunary sums 
16.11.  Vadim Gorin  Infinite beta random matrix theory 
23.11.  Felix Pogorzelski  Mathematical quasicrystals and unique ergodicity 
30.11.  Laszlo Erdös  Edge Universality for NonHermitian Random Matrices 
07.12.  Patrik Ferrari  KPZ universality in mathematics and physics 
14.12.  Erika Hausenblas  Numerical Modelling of a stochastic GrayScott system 
04.01.  Matthias Schulte  Nonstandard limits for a family of autoregressive stochastic sequences 
11.01.  Amin CojaOghlan  Disordered systems and random graphs 
18.01.  Michael Voit  Limit theorems for Bessel processes of large dimensions and free convolutions 
25.01.  Hugo DuminilCopin  Emerging symmetries in 2D percolation 
01.02.  Larry Goldstein  Relaxing Gaussian Assumptions in High Dimensional Statistical Procedures 
08.02.  Uta Freiberg  Analysis on the Stretched Sierpinski Gasket 
Summerterm 2020
Apr 27 
Thomas Kruse, University of Giessen We present new approximation methods for highdimensional PDEs and BSDEs. A key idea of our methods is to combine multilevel approximations with Picard fixedpoint approximations. We prove in the case of semilinear heat equations with Lipschitz continuous nonlinearities that the computational effort of one of the proposed methods grows polynomially both in the dimension and in the reciprocal of the required accuracy. We illustrate the efficiency of the approximation methods by means of numerical simulations. The talk is based on joint works with Weinan E, Martin Hutzenthaler, Arnulf Jentzen, Tuan Nguyen and Philippe Von Wurstemberger. 
May 4 
Cécile Mailler, University of Bath In this joint work with Nikolaos Fountoulakis, Tejas Iyer and Henning Sulzbach (Birmingham), we study a random graph model introduced by Bianconi and Rahmede in 2015. This model is a simplicial complex model that generalises Apollonian networks and the random recursive trees, by, in particular, adding random weights to the nodes. For this general model, we prove limiting theorems for the degree distribution, and confirm the conjecture of Bianconi and Rahmede on the scalefree propoerties of this random graph. 
May 11 
Andreas BasseO’Conner, Aarhus University Infinite divisible laws play a crucial role in many areas of probability theory. This class of laws corresponds exactly to all the possible weak limits of triangular arrays of random variables, due to the generalized central limit theorem, and hence infinite divisible laws are natural generalizations of the Gaussian laws. In this talk we will discuss properties and representations of infinite divisible probability measures on Banach spaces, with particular focus on their LévyKhintchine representations and their shot noise representations. We will see that these representations depend heavily on the Banach space under consideration. In particular, both the geometry of the Banach space and its “size” will play a big role. Many examples of high dimensional probability measures come from stochastic process theory, and we will illustrate the results within this framework. 
May 18 
Manuel Cabezas, Pontificia Universidad Católica de Chile Activated random walks is a system of particles which perform random walks and can spontaneously fall asleep, staying put. When an active particle falls on a sleeping one, the sleeping particle becomes active and continues moving. The system displays a phase transition in terms of the density of particles. If the density is small, all particles will eventually sleep forever, while, if the density is high, the system can sustain a positive proportion of active particles. In this talk we describe the critical behavior of the model in the totally asymmetric case. Joint work with Leo Rolla. 
May 25  Airam Blancas Benítez, Stanford University
Coalescent models for trees within trees Phylogenetic gene trees are contained within the branches of the species trees. In order to model genealogy backwards in time, of both, gene trees and species trees, simple exchangeable coalescent (snec) process are defined and characterized in talk. In particular, we study the coming down form infinity property for the so called nested Kingman. Finally, we present a model to include population structure in gene lineages. 
June 8  Geronimo Uribe Bravo, UNAM
On the profile of trees with a given degree sequence For a given (plane) tree $\tau$, let $N_i$ be the quantity of individuals with $i$ descendants and define its degree sequence as $s=(N_i)_{i\geq 1}$. We will be interested in the uniform distribution on trees whose degree sequence is $s$. We give conditions for the convergence of the profile (aka the sequence of generation sizes) as the size of the tree goes to infinity. This gives a more general formulation and a probabilistic proof of a conjecture due to Aldous for conditioned GaltonWatson trees. Our formulation contains results in this direction obtained previously by DrmotaGittenberger and Kersting. The technique, based on path transformations for exchangeable increment processes, also gives us a (partial) compactness criterion for the inhomogeneous continuum random tree. 
June 15 
Olivier Hénard, Université ParisSud Lackner and Panholzer (2015) introduced the parking process on trees as a generalization of the classical parking process on the line. 
June 22 
Adrian Gonzalez Casanova, UNAM The relation between these two important families of processes has been investigated in some cases. In particular, in a a renowned paper by seven authors, the $\beta$coalescents are obtained as a functional of two independent $\alpha$stable branching processes. 
June 29 
Antoine Lejay, Institut Élie Cartan de Lorraine (IECL)
We discuss the problem of the Monte Carlo simulation of sample paths. The Embeddable Markov Chain Schemes simulate the exact positions of a diffusion at some hitting times which are not known but only approximated. Such schemes aim at overcoming the situations in which the EulerMaruyama scheme cannot be used, because of the presence of discontinuous coefficients, interfaces, sticky points, … 
July 6 
Thomas Godland, University of Münster In this talk, I consider generate a conical tessellation of the Euclidean 
July 13 
Osvaldo Angtuncio, UNAM In this talk, we introduce the model of uniform multitype forests with a given degree sequence (MFGDS). The construction is done using the results of Chaumont and Liu 2016, and a novel path transformation on multidimensional discrete exchangeable increment processes, which is a generalization of the Vervaat transform. By mixing the laws of MFGDS, one obtains multitype GaltonWatson (MGW) forests conditioned with the number of individuals of each type (CMGW). We also obtain the joint law of the number of individuals by types in a MGW forest, generalizing the OtterDwass formula. This allows us to get enumerations of multitype forests with a combinatorial structure (plane, labeled and binary forest), having a prescribed number of roots and individuals by types. Finally, under certain hypotheses, we give an easy algorithm to simulate CMGW forests, generalizing the unitype case given by Devroye in 2012. The previous results can be considered as the first step to obtain the profile of the multitype Lévy forest. 
Winterterm 2019/20
at Ruhr University Bochum
Oct 14  Pascal Maillard, Toulouse (France) 1stable fluctuations of branching Brownian motion at critical temperature 
Oct 21  Holger Sambale, Bielefeld Higher order concentration of measure 
Oct 28  Carina Betken, Bochum Poisson cylinder processes: concentration inequalities and a CLT for the volume 
Nov 4  Erik Broman, Uppsala (Sweden) The Poisson cylinder process in Euclidean and Hyperbolic space 
Nov 11  Nina Holden, ETH Zürich (Switzerland) Cardy embedding of random planar maps 
Nov 18  Leif Döring, Mannheim Existence, Uniqueness and Explosion results for stable SDEs 
Dec 2  Hanna Döring, Osnabrück Crossing Numbers and Stress of Random Geometric Graphs 
Dec 9  Joseph Najnudel, Bristol (UK) On smooth mesoscopic linear statistics of the eigenvalues of random permutation matrices 
Jan 6  Karen Habermann, Sorbonne Université Paris (France) A semicircle law and decorrelation phenomena for iterated Kolmogorov loops 
Jan 13  Steffen Dereich, Münster A central limit theorem for averaged gradient descend in deep learning applications 
Jan 20  Quan Shi, Mannheim Measurevalued diffusions with PoissonDirichlet stationary distributions 
Jan 27  George Andriopoulos, Shanghai (China) Scaling limits of random walks in random environments on trees and related parameters 
Summerterm 2019
at Ruhr University Bochum
Apr 8 
Kristina Schubert, Dortmund, RTG 
Apr 15 
Anna Gusakova, Bochum, RTG 
May 6 
Jere Koskela, Warwick 
May 13 
Yuriy Nemish, Klosterneuburg, IST 
May 20 
Michael Soerensen, Kopenhagen 
May 27 
Anna Paola Todino, Bochum 
Jun 17 
Max Fathi, Toulouse 
Jun 24 
Miklós Kornyik, Budapest 
Jul 1 
Markus Reiss, Berlin 
Jul 8  David Damanik, Houston The FürstenbergIshii Criterion for a Positive Lyapunov Exponent and Applications to Anderson Localization 
Winterterm 2018/19
at University DuisburgEssen
Oct 8 
Abel Klein, Irvine (USA) 
Oct 8  Tobias Müller, Groningen (Netherlands) The critical probability for confetti percolation equals 1/2 
Oct 15 
Vitalii Konarovskyi, Leipzig 
Oct 22  PImeeting 
Oct 29 
Piotr Graczyk, Angers (France) 
Nov 5 
Vlada Limic, Strasbourg (France) 
Nov 12 
Wioletta Ruszel, Delft (Netherlands) 
Nov 19 
Noemi Kurt, Berlin 
Nov 26 
Tran Viet Chi, Lille (France) 
Dec 3 
Martin Slowik, Berlin 
Dec 17 
Michael Hinz, Bielefeld 
Jan 7 
Sebastian Riedel, Berlin 
Jan 14 
Mike Keane, Leiden (Netherlands) 
Jan 21 
Thomas Mikosch, Copenhagen (Denmark) and Bochum 
Jan 28 
Johannes Heiny, Bochum (RTG) 
Summerterm 2018
at Ruhr University Bochum
Apr 16 
Martin Venker, Bochum
Universality in NonHermitian Random Matrix Theory: Fixed Trace Ensembles

Apr 19 
Ciprian Tudor, Lille (France)
Variation of the solution to the wave equation

Apr 23 
Thomas Kriecherbauer, Bayreuth
Floquet Theory for Markov processes and a nonlinear generalisation

Apr 30 
Christian Döbler, Luxemburg
Normal approximation of Ustatistics via contractions

May 7 
Ilya Molchanov, Bern (Switzerland)
The semigroup of metric measure spaces and its infinitely divisible measure

May 14 
BeatriceHelen Vritsiou, Ann Arbor (Michigan, USA)
Selbergtype integrals and the variance conjecture for the Schatten classes

May 28 
Maite WilkeBerenguer, Berlin
The WrightFisher model with selection in a random environment

Jun 4 
Eliza O’Reilly, Austin (Texas, USA)
Reach of Repulsion for Determinantal Point Processes in High Dimensions

Jun 18 
Yacine BarhoumiAndréani, Zurich (Switzerland)
On the midcoefficient of a random unitary matrix

Jun 25 
Paolo Pigato, Berlin
Estimation of piecewiseconstant coefficients in a stochastic differential equation

Jul 2 
Priscilla Greenwood, Vancouver (Canada)
Quasipatterns of synchronization produced by a Mexican hat coupling of quasicycles

Jul 9 
Daniel Hug, Karlsruhe
Geometric Stability, mass transportation and stochastic geometry

Jul 16 
Piotr Graczyk, Angers (France)
Squared Bessel particle systems and Wishart processes

Winterterm 2017/18
at Ruhr University Bochum
Oct 16 
Peter Mörters, Köln
Metastability of the contact process on evolving scalefree networks 
Oct 23 
Ivan Veselic, Dortmund
Glivenko Cantelli and Ergodic Theorem on groups

Nov 6 
Anita Winter, DuisburgEssen
Brownian motion on graphlike metric spaces and the cover time bound

Nov 13 
Sergio Andraus, Tokyo
Dunkl processes and particle systems: dynamics due to the exchange interaction

Nov 20 
Masha Gordina, Connecticut
Stochastic Analysis and Geometric Functional Inequalities
Chiranjib Mukherjee, Münster
Recent developments in compact large deviation theory and applications to statistical mechanics

Nov 27 
Frank Aurzada, Darmstadt
Persistence probabilities for fractional processes

Dec 4 
Philippe Bougerol, Paris
The Pitman theorem and random walks on trees and hyperbolic spaces

Dec 11 
Mira Shamis, London
The CurieWeiss model at complex temperature

Dec 18  RTG Feedback meeting 
Jan 8 
Günter Last, Karlsruhe
How to find an extra excursion in Brownian motion

Jan 11 
Alexander Lindner, Ulm
Quasiinfinitely divisible distributions

Jan 15 
Simone Warzel, München
Localizationdelocalization transitions in effective random matrix models

Jan 22 
Apostolos Giannopoulos, Athens
On the MM*estimate for isotropic convex bodies: upper bounds for the mean norm and the mean width

Jan 2930  Workshop Statistical Mechanics 
Summerterm 2017
at TU Dortmund
April 24th  Sandra Kliem, University of DuisburgEssen Travelling wave solutions to the KPP equation with branching noise 
May, 8th  KarlTheodor Sturm, University of Bonn Heat flow, optimal transport, and Ricci curvature on metric measure spaces 
May, 15 th 
Wolfgang König, TU Berlin 
May, 22nd  Elena Pulvirenti University of Bonn
Metastability for the WidomRowlinson model 
May, 29th 
Joscha Prochno, University of Hull, UK 
June, 8th 
René Schilling, University Dresden 
June, 12th  JeanYves Welschinger, University of Lyon Expected topology of a random subcomplex in a simplicial complex 
June, 19th 
Anne Estrade, University of Paris
A test of Gaussianity based on the Euler characteristic of excursion sets 
June, 26th 
Christian Bender, University Saarbrücken 
July, 3rd 
Paul Doukhan, University CergyPontoise 
July, 10th 
Lisa Hartung, New York University 
July, 17th  Larry Goldstein, UCLA
Non asymptotic distributional bounds for the Dickman approximation of the running time of the Quickselect algorithm

Wintertherm 2016/17
at Ruhr University Bochum
October 24th  Sebastian Andres, University of Cambridge, UK Diffusion processes on Branching Brownian Motion 
November 7th  David Croydon, University of Warwick, UK Scaling limits of stochastic processes accociated with resistance forms 
November 14th 
Ngoc Mai Tran, University of Bonn 
November 21st  Christoph Külske, University of Bochum
Gibbsnon Gibbs transitions for point particles under timeevolution: the WidomRowlinson model under spin flip 
November 28th  Jan Nagel, TU München Large deviations for random matrices and sum rules 
December 5th  Julian Grothe, University of Bochum Gaussian polytopes and simplices  a cumulant based approach 
December 12th  Uta Freiberg, University of Stuttgart
Spectral asymptotics on random Sierpinski gaskets 
December 19th  RTGFeedback meeting 
January 9th 
Matthias Schulte, University of Bern
MalliavinStein method, stochastic geometry and beyond 
January 16th  Sandra Palau Calderon, University of Bath Generalisations of continuousstate branching processes 
January 23rd  Sara Mazzonetto, University of Potsdam, Lille Exact simulation of Brownian diffusions with drift admitting jumps 
January 30th  Elisabeth Werner, Case Western Reserve University Cleveland Approximation of convex bodies by polytopes 
Summertherm 2016
at University DuisburgEssen
April 18th  Jeannette Woerner, University of Dortmund An introduction to fractional processes and related limit theorems 
April 25th 
Martin Hutzenthlaler, University of DuisburgEssen 
May 2nd 
Pierre Calka, University of Rouen 
May 9th  Angelika Rohde, University of Bochum Spectral analysis of highdimensional sample covariance matrices with missing observations 
May 23rd  Maurizia Rossi, University of Luxemburg Nonuniversality of nodal length distribution for arithmetic random waves 
May 30th  Margherita Disertori, University of Bonn History dependent stochastic processes and non linear sigma models 
June 6th  Imre Barany, Hungarian Academy of sciences Budapest On the randomized integer convex hull 
June 13th  Markus Heydenreich, LMU München Scalefree percolation 
June 20th 
Ehsan Azmoodeh, University of Helsinki
An attempt to small deviations 
June 27th  Holger Kösters, Bielefeld Products of Independent Random Matrices: From Singular Values to Eigenvalues 
July 4th  Alexander Drewitz, University of Köln The maximal particle of branching random walk in spatially random branching environment 
July 11th  Sebastian Scholtes, University of Aachen Old and new on sets of positive reach 
July 18th  Hui He, University of Beijing From GaltonWatson trees to Levy trees: Scaling limits, pruning process and reduced trees 
Wintertherm 2015/16
at Ruhr University Bochum
October 26 
Sander Dommers (University of Bochum) 
November 2 
Bram Petri (University of Bonn) 
November 9 
Claudio Dursatanti (University of Bochum) 
November 16 
Nicola Kistler (University of Frankfurt) 
November 23 
Tobias Fissler (University of Bern) 
November 30 
Richard Kraaij (University of Delft) 
December 7 
Matthias Löwe (University of Münster) 
December 14 
Sabine Jansen (University of Bochum) 
December 21 
Mark Podolskij (University of Aarhus) 
January 11 
Fabian Gerle (University of DuisburgEssen) 
January 18 
Vaidotas Characiejus (University of Bochum) 
January 25 
Raghid Zeineddine (University of Dortmund) 
January 1st 
Vaidotas Characiejus(university of Bochum) 
February 8 
Arnulf Jentzen (ETH Zürich) 