Guillem Cazassus (Oxford) will speak in the differential geometry seminar on 26/02/2024 at 2pm in the Salle des Profs (9th floor building NO). Guillem’s title is *“Extending down Donaldson-Floer theory”* and his abstract is below.

*The Donaldson polynomials are powerful invariants in LowDimensional Topology: for example they are able to distinguish smoothmanifolds that are homeomorphic, but not diffeomorphic. They arerooted in theoretical physics (Yang-Mills gauge theory) and aredifficult to compute, as they involve solving a PDE (theAnti-Self-Dual equation).*

*I will present a program aimed at computing these by “cut-and-paste”operations. Specifically I will explain how to recast these into an“extended Topological Field Theory”. This will involve going fromGauge Theory to Symplectic Geometry, Hamiltonian actions andHomotopical Algebra.*