Wed, 05 Nov 2025

16:00 - 17:00
L6

Improving acylindrical actions on trees

Will Cohen
(Cambridge)
Abstract
Loosely speaking, an action of a group on a tree is acylindrical if long enough paths must have small stabilisers. Groups admitting such actions form a natural subclass of acylindrically hyperbolic groups, and interesting an feature of acylindrical actions on trees is that many interesting properties are inherited from their vertex stabilisers. In order to make use of this, it is important to have some degree of control over these stabilisers. For example, can we ask for these stabilisers to be finitely generated, or even malnormal (or finite-height)? Even stronger, if our group is hyperbolic, can we ask for the stabilisers to be quasiconvex?
 
In this talk, I will introduce acylindrical actions and some stronger and related concepts, and discuss a method known as the Dunwoody—Sageev resolution that we can use to move between these concepts and provide positive answers to the above questions in some cases.
Implementation Report: Integrating Natural Language Processing Approaches in Child and Adolescent Mental Health Services Research Using Normalisation Process Theory
Chen, H Chapman, J Tu, E Zhou, S Laing, J Fergusson, E Kormilitzin, A
Implementation Report: Integrating Natural Language Processing Approaches in Child and Adolescent Mental Health Services Research Using Normalisation Process Theory
Chen, H Chapman, J Tu, E Zhou, S Laing, J Fergusson, E Kormilitzin, A
Tight Distance Query Reconstruction for Trees and Graphs Without Long Induced Cycles
Bastide, P Groenland, C RANDOM STRUCTURES & ALGORITHMS volume 66 issue 4 (01 Jan 2025)
Random embeddings of bounded-degree trees with optimal spread
Bastide, P Legrand-Duchesne, C Müyesser, A Combinatorics, Probability and Computing 1-12 (13 Oct 2025)
Mathematical Modeling of Bone Remodeling after Surgical Menopause.
Nelson, A Yeo, E Zhang, Y Cook, C Fischer-Holzhausen, S Bruce, L Dutta, P Gholami, S Smith, B Ford Versypt, A (20 Oct 2025) https://www.ncbi.nlm.nih.gov/pubmed/41278646
Convergence of a finite volume scheme for a model for ants
Bruna, M Schmidtchen, M de Wit, O ESAIM: Mathematical Modelling and Numerical Analysis
Smartphone-based prediction of dopaminergic deficit in prodromal and manifest Parkinson’s disease
Gunter, K Groenewald, K Aubourg, T Lo, C Welch, J Razzaque, J Hillegondsberg, L Nastasa, A Ratti, P Orso, B Mattioli, P Pardini, M Raffa, S Massa, F McGowan, D Bradley, K Arnaldi, D Klein, J Arora, S Hu, M npj Digital Medicine (01 Dec 2025)
Mon, 19 Jan 2026

15:30 - 16:30
L3

The Brownian marble

Prof. Andreas Kyprianou
(Dept of Mathematics University of Warwick)
Abstract

Fundamentally motivated by the two opposing phenomena of fragmentation and coalescence, we introduce a new stochastic object which is both a process and a geometry. The Brownian marble is built from coalescing Brownian motions on the real line, with further coalescing Brownian motions introduced through time in the gaps between yet to coalesce Brownian paths. The instantaneous rate at which we introduce more Brownian paths is given by λ/g2\lambda/g^2 where gg is the gap between two adjacent existing Brownian paths. We show that the process "comes down from infinity" when 0<λ<60<\lambda<6 and the resulting space-time graph of the process is a strict subset of the Brownian Web on R×[0,∞)\mathbb R \times [0,\infty). When λ≥6\lambda \geq 6, the resulting process "does not come down from infinity" and the resulting range of the process agrees with the Brownian Web.

Advances in Quantum Computation in NISQ Era
Xie, X Zhang, X Koczor, B Yuan, X Entropy volume 27 issue 10 1074-1074 (15 Oct 2025)
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