Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

 

Thu, 27 Nov 2025
17:00
L3

Pfaffian Incidence Geometry and Applications

Martin Lotz
(University of Warwick)
Abstract

Pfaffian functions, and by extension Pfaffian and semi-Pfaffian sets, play a crucial role in various areas of mathematics, including o-minimal theory. Incidence combinatorics has recently experienced a surge of activity, fuelled by the introduction of the polynomial partitioning method of Guth and Katz. While traditionally restricted to simple geometric objects such as points and lines, focus has shifted towards incidence questions involving higher dimensional algebraic or semi-algebraic sets. We present a generalization of the polynomial partitioning method to semi-Pfaffian sets and illustrate how this leads to Pfaffian generalizations of classic results in incidence geometry, such as the Szemerédi-Trotter Theorem. Finally, we outline an application of semi-Pfaffian geometry and Khovanskii's bound to the robustness of neural networks.

Fri, 28 Nov 2025

11:00 - 12:00
L1

How to effectively manage your time

Abstract

This session will explore practical ways to manage your time effectively as a student. We’ll discuss how to find the right balance between revising and working on problem sheets, tools and strategies to help you plan your workload, and how to set realistic priorities. We’ll also talk about what kind of study balance makes sense over the Christmas break. Come along to pick up useful tips for staying organised, focused, and on top of your studies.

 

This session is likely to be most relevant for first-year undergraduates, but all are welcome.

Fri, 28 Nov 2025

11:00 - 12:00
L4

Competition and warfare in bacteria and the human microbiome

Prof Kevin Foster
(Sir William Dunn School of Pathology University of Oxford)
Abstract

Microbial communities contain many evolving and interacting bacteria, which makes them complex systems that are difficult to understand and predict. We use theory – including game theory, agent-based modelling, ecological network theory and metabolic modelling - and combine this with experimental work to understand what it takes for bacteria to succeed in diverse communities. One way is to actively kill and inhibit competitors and we study the strategies that bacteria use in toxin-mediated warfare. We are now also using our approaches to understand the human gut microbiome and its key properties including ecological stability and the ability to resist invasion by pathogens (colonization resistance). Our ultimate goal is to both stabilise microbiome communities and remove problem species without the use of antibiotics.

Fri, 28 Nov 2025

12:00 - 13:15
L3

TBA

Brian Williams
(Boston University)
Mon, 01 Dec 2025
14:15
L4

Bubble sheets and $\kappa$-solutions in four-dimensional Ricci flow

Patrick Donovan
(UNSW Sydney)
Abstract

As discovered by Perelman, the study of ancient Ricci flows which are $\kappa$-noncollapsed is a crucial prerequisite to understanding the singularity behaviour of more general Ricci flows. In dimension three, these so-called "$\kappa$-solutions" have been fully classified through the groundbreaking work of Brendle, Daskalopoulos, and Šešum. Their classification result can be extended to higher dimensions, but only for those Ricci flows that have uniformly positive isotropic curvature (PIC), as well as weakly-positive isotropic curvature of the second type (PIC2); it appears the classification result fails with only minor modifications to the curvature assumption. Indeed, with the alternative assumption of non-negative curvature operator, a rich variety of new examples emerge, as recently constructed by Buttsworth, Lai, and Haslhofer; Haslhofer himself has conjectured that this list of non-negatively curved $\kappa$-solutions is now exhaustive in dimension four. In this talk, we will discuss some recent progress towards resolving Haslhofer's conjecture, including a compactness result for non-negatively curved $\kappa$-solutions in dimension four, and a symmetry improvement result for bubble-sheet regions. This is joint work with Anusha Krishnan and Timothy Buttsworth. 

Mon, 01 Dec 2025
15:30
L5

Kazhdan‘s property T, waist inequalities, and some speculations

Roman Sauer
(Karlsruhe Institute of Technology)
Abstract

I will discuss a uniform waist inequality in codimension 2 for the family of finite covers of a Riemannian manifold whose fundamental group has Kazhdan‘s property T. I will describe a general strategy to prove waist inequalities based on a higher property T for Banach spaces. The general strategy can be implemented in codimension 2 but is conjectural in higher codimension. We speculate about the situation for lattices in semisimple Lie groups. Based on joint work with Uri Bader

Mon, 01 Dec 2025
16:00
C3

TBC

Søren Eilers
(Unviersity of Copenhagen)
Abstract

to follow

Wed, 03 Dec 2025
14:30
N3.12

DPhil Applications Q&A

Abstract

Your chance to ask Mathematrix DPhil students about the process of applying to PhD programs, including written stages and interviews! 

Thu, 04 Dec 2025

12:00 - 13:00
L3

Geometry optimisation of wave energy converters

Emma Edwards
(Department of Engineering Science University of Oxford)

The join button will be published 30 minutes before the seminar starts (login required).

Abstract

Wave energy has the theoretical potential to meet global electricity demand, but it remains less mature and less cost-competitive than wind or solar power. A key barrier is the absence of engineering convergence on an optimal wave energy converter (WEC) design. In this work, I demonstrate how geometry optimisation can deliver step-change improvements in WEC performance. I present methodology and results from optimisations of two types of WECs: an axisymmetric point-absorber WEC and a top-hinged WEC. I show how the two types need different optimisation frameworks due to the differing physics of how they make waves. For axisymmetric WECs, optimisation achieves a 69% reduction in surface area (a cost proxy) while preserving power capture and motion constraints. For top-hinged WECs, optimisation reduces the reaction moment (another cost proxy) by 35% with only a 12% decrease in power. These result show that geometry optimisation can substantially improve performance and reduce costs of WECs.

Thu, 04 Dec 2025

14:00 - 15:00
Lecture Room 3

TBA

Niall Madden
(University of Galway)
Abstract

TBA

Thu, 04 Dec 2025
16:00
Lecture Room 4

TBA

Elvira Lupoian
(University College London)
Thu, 04 Dec 2025
17:00
L3

Sharply k-homogeneous actions on Fraïssé structures

Robert Sullivan
(Charles University, Prague)
Abstract
Given an action of a group G on a relational Fraïssé structure M, we call this action *sharply k-homogeneous* if, for each isomorphism f : A -> B of substructures of M of size k, there is exactly one element of G whose action extends f. This generalises the well-known notion of a sharply k-transitive action on a set, and was previously investigated by Cameron, Macpherson and Cherlin. I will discuss recent results with J. de la Nuez González which show that a wide variety of Fraïssé structures admit sharply k-homogeneous actions for k ≤ 3 by finitely generated virtually free groups. Our results also specialise to the case of sets, giving the first examples of finitely presented non-split infinite groups with sharply 2-transitive/sharply 3-transitive actions.
Fri, 05 Dec 2025

11:00 - 12:00
L4

Cell shapes, migration and mechanics determine pattern formation during development

Dr Lakshmi Balasubramaniam
(Engineering Biology University of Cambridge)
Abstract

Blood vessels are among the most vital structures in the human body, forming intricate networks that connect and support various organ systems. Remarkably, during early embryonic development—before any blood vessels are visible—their precursor cells are arranged in stereotypical patterns throughout the embryo. We hypothesize that these patterns guide the directional growth and fusion of precursor cells into hollow tubes formed from initially solid clusters. Further analysis of cells within these clusters reveals unique organization that may influence their differentiation into endothelial and blood cells. In this work, I revisit the problem of pattern formation through the lens of active matter physics, using both developing embryonic systems and in vitro cell culture models where similar patterns are observed during tissue budding. These different systems exhibit similar patterning behavior, driven by changes in cellular activity, adhesion and motility.

Tue, 27 Jan 2026
14:00
L6

TBC

Adam Thomas
(University of Warwick)
Abstract

to follow

Tue, 10 Feb 2026
14:45
L6

TBC

Corina-Gabriela Ciobotaru
(Aarhus University)
Abstract

to follow

Thu, 19 Feb 2026

14:00 - 15:00
Lecture Room 3

TBA

Jongho Park
(King Abdullah University of Science and Technology (KAUST))
Abstract

TBA

Thu, 26 Feb 2026

14:00 - 15:00
Lecture Room 3

TBA

Carolina Urzua Torres
(TU Delft)
Abstract

TBA