Virtual Seminar on

Geometry and Topology

How to join

Zoom Meeting ID 739-035-2844

Password Zero minus the Euler characteristic of a closed oriented surface of genus 4000

Time Wed 4 pm or Thursday 9 am (or so) in KST (Korea Standard Time)


September 23 (W)

No talks

October 14 (W) 5 pm, Korea = 8 am, UK (note the time!), Zoom 739-035-2844

Henry Wilton (Cambridge)

On stable primitivity rank

The commutator length of an element w of the commutator subgroup of a group G is the minimal number of commutators needed to express w as a product of commutators. A more fruitful definition is obtained by stabilising the definition, yielding the notion of *stable* commutator length.

In the context of free groups, Puder has recently introduced the notion of *primitivity rank*, which can be thought of as a homotopical version of commutator length. In this talk, I’ll propose a stable version of primitivity rank, and state some of its properties.

October 28 (W) & more (mini-course). 9 am, Zoom 739-035-2844

Michael Landry (Washington University St. Louis)



November 25 (W) 10 am (note the time!), Zoom 739-035-2844

Kathryn Mann (Cornell)




Harry Hyungryul Baik (KAIST)

Sam Sang-hyun Kim (KIAS)

Mailing list

Click to subscribe

(please include name/institution)