Date/Time
Date(s) - 27/02/2025
3:30 pm - 4:30 pm

Speaker: Evan Scott (CUNY)

Location: Hamilton Hall, Room 312

Title: The Laudenbach-Poénaru theorem and an equivariant extension

Abstract: The Laudenbach-Poénaru theorem is a foundational part of modern, handle-calculus driven 4—manifold topology and shows a stark difference between how 1—handlebodies (particularly simple manifolds with boundary) behave in dimensions 3 and 4. Unfortunately, the theorem’s main applications and its classical proof are difficult to understand. In this talk, we’ll understand what the theorem says by contrasting with dimension 3, we’ll explain how it applies to give us Kirby diagrams and Trisections, and we’ll sketch (the non-equivariant version of) a proof given in recent joint work with Jeffrey Meier. We’ll also try to explain how this proof can be adapted to the setting where there is a finite group action on our 4—dimensional 1—handlebody and talk about some applications and interesting open questions in the equivariant setting.