## Events

20.06.2024 Oberseminar Darmstadt

Tejas Iyer (WIAS Berlin)

### Persistent hubs in generalised preferential attachment trees

Read more21.06.2024 Rhein-Main-Kolloquium

Stein Andreas Bethuelsen (University of Bergen)

### RMK Mainz

Assign to each lattice point of Z^d a Poissonian number of particles and let each of them evolve independently as discrete-time simple random walks. On top of this dynamically evolving environment we consider an additional random walk whose jump transition depends on whether there are particles present at its location or not. This is the so-called random walk on random walks model. Previous studies have concluded that this model on Z^d, d\geq1, has a diffusive scaling when the density of particles is sufficiently low or sufficiently high. We will argue that this holds for all densities for the model on Z^d with d\geq 5. Our proof of this rely on a novel domination result for the dynamic environment that, when combined with coupling arguments and standard random walk estimates, yield uniform mixing bounds for the so-called local environment process. Based on joint work, partly in progress, with Florian Völlering (University of Leipzig) Read more21.06.2024 Rhein-Main-Kolloquium

Jiří Černý (Universität Basel)

### RMK Mainz

In the presentation, I will consider two related models: the one-dimensional branching Brownian motion in random environment (BBMRE), and the randomized F-KPP equation (rFKPP). I will discuss the following natural questions: (1) Given a typical realisation of the environment, are the distributions of the maximal particle of the BBMRE (re-centred around their medians) tight? (2) For the same environment, is the width of the front of the "travelling-wave" solution to rFKPP uniformly bounded in time? Surprisingly, it turns out that the answers to these questions can be different. This highlights that, when compared to the settings of homogeneous branching Brownian motion and the F-KPP equation in a homogeneous environment, the introduction of a random environment leads to a much more intricate behaviour. The presentation is based on joint works with A. Drewitz, L. Schmitz, and P. Oswald. Read more12.07.2024 Rhein-Main-Kolloquium

Nicolas Champagnat (Nancy)

Anita Winter (Duisburg-Essen)