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.

 

Past events in this series


Tue, 20 Oct 2026
15:30
L4

The logarithmic derived category

Patrick Kennedy-Hunt
(Cambridge)
Abstract
As a scheme undergoes a simple normal crossing degeneration its coherent sheaves - and their derived category - behave unpredictably. In this talk I will describe a proposal for a category of logarithmic (quasi-)coherent sheaves associated to such a degeneration. The corresponding derived category exhibits Grothendieck-Neeman duality with the expected dualizing complex, and has a perfect diagonal (the categorical signature of smoothness).  Structures on the logarithmic derived category of the central fibre most closely resemble the smooth situation when considered relative a tropical derived category. This category is compatible with Maulik and Ranganathan’s logarithmic Donaldson—Thomas theory and has an associated (logarithmic) moduli stack of logarithmic coherent sheaves.
 
Based on joint work with De Deyn, Dell, Hu, Manali-Rahul, and Schimpf, and on separate joint work with Poiret, and Song for the moduli stack.



 

Wed, 21 Oct 2026
09:30
Exceptionally, this seminar will take place in Classroom C2.

ADHM Bundles and counting surfaces in Calabi--Yau fourfolds

Noah Dizep
(Heriot-Watt University, Edinburgh)
Abstract
The recent seminal work by Bae, Kool and Park establishes a DT type theory counting surfaces in Calabi--Yau fourfolds. I will present on joint work with R. Szabo on computing a variant of surface counts on CY4s using Diaconescu--Piazzalunga's technology of ADHM Bundles and Coulomb branch localization on a smooth, toric, projective surface.
 
We compute these enumerative invariants by computing the partition function of a topologically twisted Gauge theory similar in nature to Vafa--Witten's twist of 4d N=4 SYM. 
 
Tue, 27 Oct 2026
15:30
L4

Coproducts on 3d CoHAs

Sarunas Kaubrys
(IPMU Tokyo)
Abstract

In this talk I will discuss different types of coproducts on cohomological Hall algebras associated to 3-Calabi-Yau categories, as recently defined by Kinjo-Park-Safronov and Descombes. In general, these are actually a more exotic structure we call a vertex coproduct. I will explain the important special case of a quiver with potential. In this case, these coproducts are related to deformed Drinfeld coproducts on Yangians. I will also discuss how vertex coproducts are related to factorization type coproducts, recently defined in work of Davison-Hennecart-Kinjo-Schiffmann-Vasserot. This is joint work with Jindal and Latyntsev and work in progress with Latyntsev and Descombes.

Tue, 24 Nov 2026
15:30
L4

TBA

Federico Ardila
(Queen Mary University of London)
Tue, 08 Dec 2026
15:30

TBA

Yoav Len
(Mathematical Institute (University of St Andrews))