3 papers
math.GR2022
Coarse fixed point properties
Romain Tessera, Jeroen Winkel
We investigate fixed point properties for isometric actions of topological groups on a wide class of metric spaces, with a particular emphasis on Hilbert spaces. Instead of requiri…
math.FA2022
Cycles in graphs with geometric property (T)
Jeroen Winkel
We show that a sequence of graphs with geometric property (T) has many small cycles. We also show that when a small part of a sequence of graphs with geometric property (T) is chan…
math.QA2019
The fundamental group of a noncommutative space
Walter D. van Suijlekom, Jeroen Winkel
We introduce and analyse a general notion of fundamental group for noncommutative spaces, described by differential graded algebras. For this we consider connections on finitely ge…