Thu, 04 Jun 2026
15:00
C3

Some facts about ε-harmonic maps

Andrew Roberts
(Leeds)
Abstract

The ε-energy is a regularisation of the Dirichlet energy introduced by Tobias Lamm. Like the famous Sacks-Uhlenbeck regularisation this greatly improves the existence and regularity theory. When we take the limit of a sequence of ε-harmonic maps with the parameter ε decreasing to 0 these converge, in the standard bubbling sense, to harmonic maps, which we hope to extract information about. I will talk about some recent results for these sequences, being when we might hope to have no loss of energy and no neck forming and what sort of harmonic maps we can obtain in the limit.

Fri, 22 May 2026
15:00
C5

The special McKay correspondence and homological mirror symmetry for orbifold surfaces

Bogdan Simeonov
(Imperial)
Abstract

Given a cyclic subgroup G of GL(2,C) acting on C^2, it was first noticed by Wunram in the 80s that there is a correspondence between certain special representations of G and the exceptional curves appearing in the minimal resolution Y of the surface singularity C^2/G. In modern terms, this was reformulated by Ishii and Ueda as the existence of a fully faithful functor from the derived category of sheaves of Y to the G-equivariant derived category of C^2. In this talk, I will describe a mirror symmetric interpretation of this which exhibits the fully faithful inclusion in algebraic geometry as a sequence of positive Lefschetz stabilizations in symplectic geometry.

Wed, 29 Apr 2026

16:00 - 17:00
L5

Computations of Floer Lasagna Modules

Colin McCulloch
(Mathematical Institute University of Oxford)
Abstract

Skein lasanga modules are a smooth 4-manifold invariant that was introduced by Morrison, Walker and Wedrich using Khovanov homology. This invariant was recently used by Ren and Willis to give the first analysis free proof of the existence of exotic 4-manifolds. However, even for simple handlebodies it remains difficult to compute. A generalisation was introduced by Chen using Knot Floer homology, which in principle should be easier to compute due to cabling formulas for knot Floer homology. I will give a general introduction to lasagna modules assuming no knowledge of Khovanov or knot Floer homology, and then explain some methods, from upcoming work, for computing Floer Lasagna modules.

Banner for event - Shakespeare against backdrop of the Globe
Shakespeare’s work provides a snapshot of how people made sense of the world around them: how they solved problems (how large is an opposing army?) and how they navigated a complex environment (does the sun rise in the east?). In this talk Paul will explore how scientific and technological ideas are woven into Shakespeare’s plays and sonnets through actions, words and conversations between characters.
Real-time analytical insights for disease surveillance and response during the severe drought and food security crisis, Somalia 2022-2023
Polonsky, J Muhammad, F Lubogo, M Shube, M Jama, M Thompson, R Malik, S Conflict and Health
Robust estimation of the time-dependent reproduction number in the presence of weekend reporting effects
Ogi-Gittins, I Steyn, N Kaye, A Hill, E Thompson, R BMC Global and Public Health
HNN extensions and embedding theorems for groups
Bridson, M Nyberg-Brodda, C Journal of the London Mathematical Society
Fri, 01 May 2026

12:00 - 13:30
L5

Holographic Correlators for Non-Conformal Maximally Supersymmetric Yang-Mills

Pieter Bomans
(DESY)
Abstract

Gauge/gravity duality is more than AdS/CFT.  In this talk I will discuss how the holographic dictionary generalises to non-conformal settings, focusing on maximally supersymmetric Yang-Mills theories in diverse dimensions and their Dp-brane supergravity duals. Scaling covariance replaces conformal invariance as the unifying principle on both sides of the duality. On the gravity side, I will show how to systematically organise effective actions and Witten diagram rules for arbitrary correlators of scalar and spin-1 Kaluza-Klein modes. On the field theory side, scale covariance fixes the kinematic structure of 2- and 3-point functions at strong coupling, with the latter admitting closed-form expressions in terms of Appell functions. I will illustrate these results with explicit examples, focussing on 3d MSYM.

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