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.
Fri, 22 May 2026
15:00
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, 03 Jun 2026
15:00
15:00
C6
Decombinatorialisation
Heath Pearson
(Nottingham)
Abstract
This is a case study in approaching algebraic-geometric questions by first solving them in a combinatorially tractable class, and then generalising the findings through a sequence of increasingly general classes. The end goal is a proof of the general case. We call this process a ``decombinatorialisation''.
Executing such a process remains a lofty goal, and here we present only the first steps of what could be considered a decombinatorialisation. In this talk, we explore the Mukai conjecture on the characterisation of powers of projective spaces among Fano varieties. We will see how over time, generalisations of its proof in the case of toric Fano varieties have emerged.
In this setting we will explore two possible decombinatorialisations: via the class of spherical Fano varieties, and via a class of Fanos embedded into toric varieties via the Cox ring.
Thu, 04 Jun 2026
15:00
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.