22–25 Sept 2025
Palazzo del Castelletto
Europe/Rome timezone

(1st lesson) Curtains, walls and stable cylinders

22 Sept 2025, 11:30
1h
Aula Dini (Palazzo del Castelletto)

Aula Dini

Palazzo del Castelletto

Via del Castelletto, 17/1, 56126 Pisa PI

Speaker

Dr Davide Spriano (Christ Church College, Oxford University)

Description

In this talk we will discuss a generalization of Sageev’s wallspace construction that allows to study the geometry of certain spaces by combinatorial properties of certain walls. Specifically, we’ll look at the interactions with hyperbolicity and focus on two applications. In CAT(0) spaces, these techniques allow to construct a “universal hyperbolic quotient”, called the curtain model, that is analogous to the curve graph of a surface. When focusing on a space that is already hyperbolic, the construction can be used to improve its fine properties, and in particular we address a conjecture of Rips and Sela and show that residually finite hyperbolic groups admit globally stable cylinders. This is joint work with Petyt and Zalloum.

Primary author

Dr Davide Spriano (Christ Church College, Oxford University)

Presentation materials

There are no materials yet.