tba - Max Dehn Seminar, Salt Lake City, 30th of October 2019;
"Between Tits buildings and free factor complexes" - Southampton-Bielefeld Geometric Group Theory Meeting, Southampton, September 2019;
"Between Tits buildings and free factor complexes" - Algebra/Topology Seminar, Copenhagen, September, 2019;
"Parabolic subgroups and spherical complexes for Out(RAAGs)" - Oberseminar Modelltheorie, Geometrie und Gruppentheorie, Münster, June 2019;
"Topology of free factor complexes" - AG-Seminar Topologie, Karlsruhe, June 2019;
"Coset complexes and the Cohen-Macaulay property" - Oberseminar Algebra und Geometrie, Magdeburg, April 2019;
"Topology of free factor complexes" - SPP 2026 - Geometry at infinity conference, Münster, April 2019; Slides of this talk
"Reflections and harmonies: Coxeter groups in music theory" - SYMBol, Bielefeld, February 2019
"Free factors at infinity" - Bielefeld-Münster Seminar on Groups, Geometry and Topology, January 2019
"Finding fibres for free factors" - Junior Topology and Group Theory Seminar, Oxford, October 2018
"Higher connectivity of free factor complexes" - Poster presented at Geometric Group Theory in Campinas, July 2018
"Buildings and the free factor complex" - Junior Geometry and Topology Seminar (GATEWAY), Warwick, April 2018
"Out(F_{n}) and Outer Space" - BKMR Research Seminar on Geometric Group Theory, Münster, August 2017
"Higher generating subgroups in Aut(F_{n}) and GL_{n}(ℤ)" - Bielefeld-Münster Seminar on Groups, Geometry and Topology, July 2017
"Bases in non-standard models of the theory of free groups" - Oberseminar Gruppen und Geometrie, Bielefeld, June 2016
"Weight in non-standard models of the theory of free groups" - Oberseminar Modelltheorie, Geometrie und Gruppentheorie, Münster, May 2016
"Weight in non-standard models of the theory of free groups" - Models and Groups 6, Istanbul, March 2016
In October and November 2019, I am visiting Mladen Bestvina at the University of Utah.
In October and November 2018, I visited Ric Wade at the University of Oxford.
I am organising a weekly meeting on geometric group theory in Bielefeld: Friday GGT.
I was one of the organisers of the conference Outer Space in Bielefeld which took place in Bielefeld from 24th to 26th of September 2019.
I was one of the organisers of the block seminar Arithmetic groups and Rigidity which took place in Bielefeld from 21st to 23rd of March 2018. A shortened pdf-version of the introduction I gave at this seminar can be found here.
The following link leads to a petition asking to free Tuna Altınel, who was arrested in Turkey: Free Tuna Altınel. Further information can be found here.
I am a member of the DFG priority programm "Geometry at infinity": SPP 2026.