Publications
Most of these are joint work; full versions are available on arXiv. Topics are mainly in model theory, combinatorics and geometric group theory.
Rob Sullivan, Jeroen Winkel
Let M be a Fraïssé structure. We refer to the class of structures embeddable in M as the ω-age of M and study two properties of universality for the corresponding automorphism groups.
Thomas Bernert, Rob Sullivan, Jeroen Winkel, Shujie Yang
We show simplicity of the automorphism groups of the generic n-hypertournament and the semigeneric tournament, and determine the normal subgroups of the automorphism groups of several other ultrahomogeneous oriented graphs.
Rob Sullivan, Jeroen Winkel
We characterise the infinite sunflower property for countable ultrahomogeneous relational structures with strong amalgamation, and show that all free amalgamation classes with a single vertex isomorphism-type have the finite sunflower property.
Aleksandra Kwiatkowska, Rob Sullivan, Jeroen Winkel
We investigate the relationship between the presence of a stationary weak independence relation on a Fraïssé structure M, and extensibility of the ω-age of M.
Aleksandra Kwiatkowska, Rob Sullivan, Jeroen Winkel
We study embeddings into the generic (random) countable partial order and the structural properties they reveal.
Andreas Lietz, Jeroen Winkel
We connect infinite hat-guessing problems to combinatorial properties of large cardinals.
Tim de Laat, Federico Vigolo, Jeroen Winkel · Journal of Operator Theory (to appear)
We study Roe algebras of warped spaces through the lens of dynamical propagation, relating coarse geometry to the dynamics of the warping action.
Romain Tessera, Jeroen Winkel
We introduce and study coarse analogues of fixed point properties for group actions, connecting them to large-scale geometry of metric spaces.
Jeroen Winkel · Groups, Geometry, and Dynamics
We show that a sequence of graphs with geometric property (T) has many small cycles, and prove stability of the property under small perturbations.
Jeroen Winkel · Journal of Functional Analysis, 281(8), 109148
We extend the notion of geometric property (T) beyond the discrete setting and prove several characterisations.
Walter D. van Suijlekom, Jeroen Winkel · Algebras and Representation Theory
We propose a notion of fundamental group for noncommutative spaces, building on spectral triples and covering theory in the operator-algebraic setting.
Jeroen Winkel · PhD thesis, Westfälische Wilhelms-Universität Münster
Doctoral thesis on coarse geometry, geometric property (T), expander sequences and rigidity phenomena for metric spaces and groups. Supervised by Prof. Dr. Tim de Laat.