Interactions between symplectic geometry, combinatorics and number theory (14722.0073)


The "ColMar" Interactions




The seminar "Interactions" joins the teams of two universities: that of Cologne, and that of Marburg, therefore the name "ColMar** Interactions". The goal is to explain some very recent developments in the field of equivariant topology and equivariant symplectic geometry.

The organisers are:

Oliver Goertsches (

Panagiotis Konstantis (

myself (


* In the summer semester 2022 the seminar was organised by the University of Marburg only. Here you can find the link to the seminar website for this semester:


* Previous talks in the winter semester 2021/2022:

21.10.21, 14:30-16:00: Nicholas Lindsay (U. of Cologne), "Hamiltonian S^1-actions on complete intersections"

17.11.21, 12:30-14:00: Anton Ayzenberg (HSE University), "Face posets of equivariantly formal torus actions"

09.12.21, 14:30-16:00: Chris McDaniel (Endicott College), "A GKM Description for the Equivariant Coinvariant Ring of a Pseudo Reflection Group"

16.12.21, 14:30-16:00: Lisa Jeffrey (U. of Toronto), "Poisson maps between character varieties: gluing and capping"

* Link to talks in the academic year 2020/2021:


** It is also worth noticing that in Italian "colmare" means "to bridge", and we like bridges, because they allow interactions...