A homogenised model for dispersive transport and sorption in a heterogeneous porous medium
Auton, L
Dalwadi, M
Griffiths, I
(15 Oct 2024)
Human brain changes after first psilocybin use
Lyons, T
Spriggs, M
Kerkelä, L
Rosas, F
Roseman, L
Mediano, P
Timmermann, C
Oestreich, L
Pagni, B
Zeifman, R
Hampshire, A
Trender, W
Douglass, H
Girn, M
Godfrey, K
Kettner, H
Sharif, F
Espasiano, L
Gazzaley, A
Wall, M
Erritzoe, D
Nutt, D
Carhart-Harris, R
Tue, 11 Feb 2025
16:00
16:00
C3
Homology and K-theory for self-similar group actions
Alistair Miller
(University of Southern Denmark)
Abstract
Self-similar groups are groups of automorphisms of infinite rooted trees obeying a simple but powerful rule. Under this rule, groups with exotic properties can be generated from very basic starting data, most famously the Grigorchuk group which was the first example of a group with intermediate growth.
Nekrashevych introduced a groupoid and a C*-algebra for a self-similar group action on a tree as models for some underlying noncommutative space for the system. Our goal is to compute the K-theory of the C*-algebra and the homology of the groupoid. Our main theorem provides long exact sequences which reduce the problems to group theory. I will demonstrate how to apply this theorem to fully compute homology and K-theory through the example of the Grigorchuk group.
This is joint work with Benjamin Steinberg.
A scholarship for a student on the MSc Mathematical Science or MSc in Mathematical Modelling and Scientific Computing.
Mon, 11 Nov 2024
17:00
17:00
L1
The Brooke Benjamin Lecture in Fluid Dynamics: The Elusive Singularity
Professor Peter Constantin
(Princeton University)
Abstract
The Seventeenth Brooke Benjamin Lecture 2024
The Elusive Singularity
I will describe the open problems of singularity formation in incompressible fluids. I will discuss a list of related models, some results, and some more open problems.
Date: Monday, 11 November 2024
Time: 5pm GMT
Location: Lecture Theatre 1, Mathematical Institute
Speaker: Professor Peter Constantin
Fri, 01 Nov 2024
12:00 -
13:00
Quillen Room
The Bruhat-Tits building
Mick Gielen
(University of Oxford)
Abstract
The Bruhat-Tits building is a crucial combinatorial tool in the study of reductive p-adic groups and their representation theory. Given a p-adic group, its Bruhat-Tits building is a simplicial complex upon which it acts with remarkable properties. In this talk I will give an introduction to the Bruhat-Tits building by sketching its definition and going over some of its basic properties. I will then show the usefulness of the Bruhat-Tits by determining the maximal compact subgroups of a p-adic group up to conjugacy by using the Bruhat-Tits building.
Tue, 21 Jan 2025
15:00
15:00
L6
Counting non-simple closed geodesics on random hyperbolic surfaces
Laura Monk
Abstract
The aim of this talk is to present new results related to the length spectrum of random hyperbolic surfaces. The Weil-Petersson model is a beautiful probabilistic model that was popularised by Mirzakhani to study random hyperbolic surfaces. In this continuous model, it is easy to argue that there exists a density function V_g(l) which "counts" how many closed geodesics of length l an average surface of genus g contains. In the case where we only count simple geodesics (with no self-intersections), Mirzakhani proved explicit formulas for this density, writing it as a polynomial function that can be interpreted in terms of volumes of moduli spaces. I will present joint work with Nalini Anantharaman where we obtain new explicit formulas for any fixed topology. Notably, I will present new coordinate systems on Teichmüller spaces in which the Weil-Petersson volume has a surprisingly simple expression.
Though purely geometric, those results were obtained in a project related to the spectral gap of the Laplacian. I will present applications of the techniques presented in this talk to this problem at the RMT seminar. Both talks will be disjoint and independent, with the intention that they can be viewed either separately or together.
