Embeddings into the ultrapower of the Jiang-Su algebra
Pi, J
Bouwen, B
(13 Jun 2025)
Welcome to the Week 9 Bulletin! See below for all relevant news and announcements.
To suggest an item for a future bulletin, please email @email.
Frequency synchronization induced by frequency detuning.
Ocampo-Espindola, J
Bick, C
Motter, A
Kiss, I
Science advances
volume 11
issue 24
eadu4114
(11 Jun 2025)
Community detection on directed networks with missing edges
Pedreschi, N
Lambiotte, R
Bovet, A
Journal of Physics: Complexity
(18 Jun 2025)
Lifting couplings in Wasserstein spaces
Perrone, P
Compositionality
volume Volume 7 (2025)
(07 May 2025)
Wed, 25 Jun 2025
15:00
15:00
Boundary cubulation is a pathway to residual finiteness
Thomas Ng
(Brandeis University)
Abstract
Actions on CAT(0) cube complexes are powerful geometric tool for both algebraically decomposing groups and establishing subgroup separability results. I will describe boundaries associated to hyperbolic and relatively hyperbolic groups. With a focus on (quotients of) free products, I will discuss variations on a boundary criteria of Bergeron—Wise for exhibiting cocompact actions on CAT(0) cube complexes. I will explain some ideas on how to use these tools to show that most (small-cancellation or random density) quotients of free products preserve residual finiteness. This is based on multiple joint works with subsets of Einstein, Krishna MS, Montee, and Steenbock.