Geometry and Analysis on Groups Research Seminar

"Geometry and Analysis on Groups" Research Seminar

Time: 2017.01.24, 15:00–17:00
Location: Seminarraum 9, Oskar-Morgenstern-Platz 1, 2.Stock
Title: "Coarse medians and Property A."
Speaker: Ján Špakula (University of Southampton)
Abstract: Coarse medians were invented recently by Brian Bowditch (2011), with the aim of providing a common framework for both hyperbolic groups and mapping class groups. Loosely speaking, coarse median spaces are metric spaces which are locally approximable by CAT(0) cube complexes. The "rank one" situation corresponds exactly to the case of hyperbolic groups, which are (in the appropriate sense) locally approximable by trees (= rank one CAT(0) cube complexes).

Our main result is that coarse median spaces of finite rank have property A. This provides an alternative proof of the result of Y. Kida (2005) that mapping class groups have property A.

This is a joint work with Nick Wright.