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University of York Geometry, Analysis and Mathematical Physics seminar 2026-27
All are welcome to attend the seminar, which usually takes place at 2:15pm on Tuesdays in the Topos during term time. (Directions to the Topos)
Autumn Semester 2026
Spring Semester 2027
| Date | Speaker | Title |
| 2 February | | |
| 9 February | | |
| 16 February | | |
| 23 February | | |
| 2 March | | |
| 9 March | | |
| 16 March | | |
| 4 April | | |
| 11 April | | |
| 18 April | | |
| 25 April | | |
Previous years' seminars
2025-26
2024-25
2023-24
2022-23
2021-22
2020-21
2019-20
Abstracts
10 November. Matthew Habermann (Imperial)
Title. Dubrovin’s conjectures in the Landau-Ginzburg setting
Abstract. Landau-Ginzburg (LG) models are the natural mirror candidates to Fano manifolds and have an enumerative theory analogous to quantum cohomology, known as FJRW theory. In this talk, I will begin by giving an overview of these ideas, keeping a running comparison to quantum cohomology in order to explain some of the similarities and subtleties. I will then briefly explain the notion of Frobenius manifolds, how they arise in FJRW theory and how Dubrovin’s conjectures for Fano varieties lead to natural analogues in this LG setting. Finally, I would like to discuss work-in-progress in collaboration with Yefeng Shen and Weiqiang He.
17 November. Luke Jeffreys (Bristol)
Title. On McMullen’s expander graph conjecture for \(SL(2,\mathbb{Z})\)-orbits
Abstract. Square-tiled surfaces (aptly named) are surfaces obtained by gluing together a collection of unit squares along their sides (the square torus being the simplest example). These surfaces are special cases of translation surfaces, whose moduli space carries a natural action of the group \(SL(2,\mathbb{R})\). The famous works of Eskin–Mirzakhani and Eskin–Mirzakhani–Mohammadi were concerned with understanding the orbits of this action.
This \(SL(2,\mathbb{R})\)-action restricts to an action of \(SL(2,\mathbb{Z})\) on square-tiled surfaces, and the orbits under this restricted action can be transformed into finite regular graphs. It is a long-standing conjecture of McMullen that a specific family of these orbit graphs in genus two forms a family of expander graphs. I will discuss the history of this conjecture and recent progress towards it obtained in joint works with Matthew de Courcy-Ireland, Carlos Matheus and Josh Southerland.
24 November. Shing-Tak Lam (Warwick)
Title. Semistability and asymptotics of geometric flows
Abstract. In complex geometry, a central theme is the relationship between algebro-geometric stability and the existence of canonical metrics. Examples of this include the Hitchin-Kobayashi correspondence for holomorphic vector bundles, and the Yau-Tian-Donaldson conjecture for varieties. In this talk, I will discuss a parabolic analogue of these results, relating the asymptotics of the associated geometric flows to algebro-geometric filtrations defined by Haiden-Katzarkov-Kontsevich-Pandit and Ibáñez Núñez.
Last updated 12 November, 2026
