Talks in the research group seminar

The joint seminar of the research groups Topology & Geometric Group Theory and Metric Geometry takes place in the seminar room 2.058 on Thursdays at 15:45 during the lecture periods.

More information about individual talks can be found on their respective sites as soon as it becomes available.

Talks during summer semester 2025
Date	Title	Speaker
31.07.2025	Extending BNS Theory: Homotopical Σ-Invariants for Locally Compact Groups	Kai-Uwe Bux
29.07.2025	Embedding groups into acyclic groups	Xiaolei Wu
24.07.2025	The generic enumerated group is boundedly acyclic	Caterina Campagnolo
22.07.2025	On bireversible automata and automorphisms of Cayley graphs	Dominik Francoeur
06.05.2025	Finiteness properties of totally disconnected locally compact groups	Laura Bonn
24.04.2025	Introduction to Property (T)	Claudio Llosa Isenrich

Talks during winter semester 2024/25
Date	Title	Speaker
06.02.2025	Automata and groups part 3: Automata and self-similarity	Eduard Schesler
30.01.2025	Automata and groups part 2: Finite state automata and amenability	Eduard Schesler
23.01.2025	Automata and groups part 1: Finite state automata	Eduard Schesler
09.01.2025	The homological Dehn functions of Leary’s groups	Jannis Weis
17.12.2024	Strong rigidity for high dimensional analogues of hyperbolic 3-manifold groups	Christoforos Neofytidis
12.12.2024	The Dehn function of Thompson's group T	Matteo Migliorini
5.12.2024	Spectral gap absorption principle for simple groups	Yuval Gorfine
3.12.2024	Boundary Representations of Locally Compact Hyperbolic Groups	Michael Glasner
28.11.2024	The Boone--Higman Conjecture for groups acting on locally finite trees	Claudio Llosa Isenrich
21.11.2024	Cohomological properties of Neretin's group	Sofiya Yatsyna
21.11.2024	A fixed point subgroup of neretin's group	Lewis Molyneux
19.11.2024	Non-abelian expansion in octonionic hyperbolic manifolds.	Mikolaj Fraczyk
14.11.2024	On groups whose cogrowth series is the diagonal of a rational series	Alex Bishop

Talks during summer semester 2024
Date	Title	Speaker
25.07.2024	Weakly bounded and bounded cohomology classes: a finitely presented counterexample	Dario Ascari
25.07.2024	Coherence of low-dimensional groups	Jonas Seiler
18.07.2024	Hyperbolic groups of cohomological dimension 2	Rob Kropholler
11.07.2024	Some coarse geometric applications of finitely $\mathcal{F}$-amenable group actions	David Rosenthal
27.06.2024	(Non)-vanishing of high-dimensional group cohomology	Benjamin Brück
02.05.2024	A dynamical criterion for vanishing homology growth	Matthias Uschold
18.04.2024	The length of mixed identities for finite groups	Jakob Schneider

Talks during winter semester 2023/24
Date	Title	Speaker
15.02.2024	Bounded Generation of linear groups by diagonalisable elements	Segev Gonen Cohen
08.02.2024	Profinite flexibility and rigidity of Coxeter groups	Olga Varghese
06.02.2024	Conjugacy and dynamics in tree almost automorphism groups	Waltraud Lederle
01.02.2024	Arbitrarily high dimensional hyperbolic right-angled Coxeter groups that virtually fiber	Gangotryi Sorcar
25.01.2024	Mapping Class Group Action on de Rahm Classes	Federica Bertolotti
18.01.2024	Even Artin groups of FC-type	Yago Antolin
rescheduled, tba	Conformal Dimension of the Boundary for Hyperbolic Coxeter Groups	Julia Heller
14.12.2023	Dehn functions of (central products of) nilpotent groups	Jerónimo García-Mejía
07.12.2023	A human property (T) proof for high-rank Aut(F_n)	Martin Nitsche
23.11.2023	The Cohen-Lyndon property and asphericity in small-cancellation	Macarena Arenas
16.11.2023	Lattices of minimal covolume in SL(n,R)	François Thilmany
09.11.2023	Bounded cohomology and generalized knots	Thorben Kastenholz
02.11.2023	Cohomological properties of classical arithmetic groups	Yuri Santos Rego
26.10.2023	Hyperbolic manifolds fibering over the circle	Matteo Migliorini

Talks during summer semester 2023
Date	Title	Speaker
27.07.2023	Σ-Invariants for nilpotent groups	Kevin Klinge
20.07.2023	Finite quotients of generic free-by-cyclic groups	Sam Hughes
13.07.2023	Finiteness properties of subgroups of hyperbolic groups	Claudio Llosa Isenrich
06.07.2023	From symmetric spaces to generalized buildings	Raphael Appenzeller
22.06.2023	Kazhdan constants for Chevalley groups over the integers	Marek Kaluba
15.06.2023	Double-coset zeta functions for groups acting on trees: a local-to-global approach	Bianca Marchionna
25.05.2023	Sublinear rigidity of lattices in semisimple Lie groups	Ido Grayevsky
04.05.2023	Combining Papasoglu's trick with simplicial volume	Hannah Alpert
27.04.2023	Geometry and rigidity of quasi-isometries of horospherical products	Tom Ferragut
25.04.2023	Degrees of maps and multiscale geometry	Fedya Manin

Talks during winter semester 2022/23
Date	Title	Speaker
30.03.2023	The L^1-metric on Diff_0(M,area)	Michał Marcinkowski
09.02.2023	The space of metric structures on hyperbolic groups	Eduardo Oregon Reyes
26.01.2023	An l_1-norm inequality for complete manifolds	Caterina Campagnolo
19.01.2023	Group actions with spectral gap on surfaces	Tim de Laat
22.12.22	C^0 local rigidity of boundary actions by higher rank lattices (part II)	Chris Connell
15.12.22	C^0 local rigidity of boundary actions by higher rank lattices (part I)	Chris Connell
08.12.22	C^0 local non-rigidity of boundary actions of nonpositively curved lattices	Chris Connell
24.11.2022	Quantum mechanics and semi-definite optimization	Marek Kaluba
10.11.2022	Solvable, maximal and singular subgroups of arithmetic lattices	Alessandro Carderi
03.11.2022	Algebraic fibring and L^2-Betti numbers	Sam Fisher
27.10.2022	Lie groups with a small space of metric structures	Gabriel Pallier

Talks during summer semester 2022
Date	Title	Speaker
28.07.22	Embedding amenable groups into a hyperbolic space	Romain Tessera
21.07.22	Half free, half direct	Gheysens Maxime
14.07.22	Fungible obstruction to embedding 2-complexes in 4-space	Tam Nguyen Phan
30.06.22	Higher Property (T) - Part 2	Roman Sauer
23.06.22	Higher Property (T)	Roman Sauer
12.05.22	The cost of point processes on groups	Samuel Mellick
06.05.22	Virtually free groups are Hilbert-Schmidt stable	Maria Gerasimova
21.04.22	On twisted l^2-Betti numbers	Jan Boschheidgen

Talks during winter semester 2021/22
Date	Title	Speaker
10.02.22	L1 full groups of flows	François Le Maître
03.02.22	Kähler groups and finitely generated groups acting on trees	Francisco Nicolás
27.01.22	Trees beyond the line	Michele Triestino
16.12.21	Computer proofs for Property (T), and SDP duality	Martin Nitsche
09.12.21	Allosteric actions of surface groups	Matthieu Joseph
02.12.21	On the nature of subgroups of direct products of free groups	Claudio Llosa Isenrich
25.11.21	Homology growth of right-angled Artin group	Boris Okun
24.11.21	Variations of a conjecture of Singer	Grigori Avramidi
04.11.21	Piece by piece, we make our groups full	Alessandro Carderi
28.10.21	Maps with small pre-images	Tam Nguyen-Phan

Talks during summer semester 2021
Date	Title	Speaker
08.07.21	On property (T) for SL(n,Z) and Aut(F_n)	Marek Kaluba
01.07.21	On Wedderburn-Artin decomposition and property (T) for Aut(F_5)	Marek Kaluba
24.06.21	Computational aspects of Kazhdan’s property (T)	Marek Kaluba
17.06.21	Classical techniques for establishing Property (T)	Tobias Hartnick
10.06.21	Properties of Kazhdan- and Haagerup-type in the context of modern analytic group theory	Tobias Hartnick
13.05.21	Virtual fibering and group rings of RFRS groups, II	Kevin Klinge
06.05.21	Virtual fibering and group rings of RFRS groups, I	Kevin Klinge
29.04.21	Introduction to BNS-invariants	Claudio Llosa
22.04.21	More on group algebras and skew-fields	Roman Sauer
15.04.21	Kaplansky’s conjectures	Giles Gardam

Talks during winter semester 2020/21
Date	Title	Speaker
18.03.2021	Quantitative Topology V	Georg Frenck
04.03.2021	Quantitative Topology IV	Georg Frenck
25.02.2021	Quantitative Topology III	Roman Sauer
18.02.2021	Enlarging Riemannian Manifolds	Daniel Raede
11.02.2021	Quantitative Topology II	Roman Sauer
04.02.2021	Quantitative topology I	Tam Nguyen Phan
17.12.2020	On Novikov rings and flat modules	Kevin Klinge
26.11.2020	On totipotent and highly transitive actions of free groups	Alessandro Carderi
19.11.2020	On the profinite rigidity of higher rank lattices (part 2)	Holger Kammeyer
12.11.2020	On the profinite rigidity of higher rank lattices	Holger Kammeyer
05.11.2020	A funny encounter with immersions of spheres	Tam Nguyen Phan

Talks during summer semester 2020
Date	Title	Speaker
11.06.2020	The Euler characteristic of Out(Fn) and renormalized topological field theory	Michael Borinsky
04.06.2020	Refined Alexandrov-topology and the semicategory of chronological path classes	Martin Günther
28.05.2020	tba	Georg Frenck
14.05.2020	Analytic Torsion Part 2	Benjamin Waßermann
07.05.2020	Analytic Torsion	Benjamin Waßermann
30.04.2020	The noncommutative rank of Lie Groups	Holger Kammeyer
23.04.2020	Introdution to linear algebraic groups	Nico Stucki

Talks during winter semester 2019/20
Date	Title	Speaker
23.01.2020	Hypersurfaces Representing a Codimension-1 Homology Class	José Pedro Quintanilha
12.12.2019	Stable integral simplicial volume of 3-manifolds	Marco Moraschini
28.11.2019	l²-invariants of locally symmetric spaces	Zhicheng Han
21.11.2019	Bounded cohomology, amenable covers, and classifying spaces of families of subgroups	Roman Sauer
07.11.2019	Cohomological Induction and uniform measure equivalence	Thomas Gotfredsen

Talks during summer semester 2019
Date	Title	Speaker
12.07.2019	On systolic growth of nilpotent Lie groups and their lattices	Yves Cornulier
07.06.2019	Topology of free factor complexes	Benjamin Brück
24.05.2019	Adelic geometry of numbers	Adrian Lomas
08./09./10.05.2019	Mini-Lecture Series: Dynamics of horospherical subgroups of groups acting on trees	Vladimir Finkelshtein

Talks during winter semester 2018/19
Date	Title	Speaker
21.02.2019	Invariants for Sublinearly biLipschitz Equivalence	Gabriel Pallier
31.01.2019	Arithmeticity and Thinness of hypergeometric groups	Jitendra Bajpai
24.01.2019	Pseudo-arithmetic hyperbolic lattices	Olivier Mila
17.01.2019	Topology of ends of nonpositively curved manifolds	Tam Nguyen-Phan
10.01.2019	Homologieschranken für hyperbolische Orbifaltigkeiten	Hartwig Senska
15.11.2018	Nichtkreuzende Partitionen und deren Automorphismen	Julia Heller

Talks during summer semester 2018
Date	Title	Speaker
19.07.2018	Probabilistic finiteness properties for profinite groups	Matteo Vannacci
06.07.2018	Simplicial volume and macroscopic scalar curvature	Sabine Braun
05.07.2018	Reidemeister torsions on 3 manifolds character varieties and incompressible surfaces	Leo Benard
28.06.2018	Geometrie der Coxetergruppen und Anwendungen auf algebraische Probleme	Alexis Marchand
21.06.2018	Analytic L²-invariants and Zeta-Regulization	Benjamin Waßermann
14.06.2018	Profinite rigidity of graph manifolds	Gareth Wilkes
24.05.2018	The Teichmüller TQFT volume conjecture for twist knots	Fathi Ben Aribi
18.05.2018	An introduction to ideal simplicial volume	Marco Moraschini
26.04.2018	Farber sequences of lattices	Alessandro Carderi
19.04.2018	Subgroup growth of right-angled Coxeter groups	Jean Raimbault

Talks during winter semester 2017/18
Date	Title	Speaker
01.02.2018	Diophantine properties of groups of total automorphisms	Vladimir Finkelshtein
18.01.2018	The Gromov norm for degree 4 classes	Hester Pieters
11.01.2018	On characteristic classes of exotic manifold bundles	Manuel Krannich
19.12.2017	Betti numbers, L²-multiplicities and an equivariant approximation theorem	Steffen Kionke
21.11.2017	Exploring the nature of approximate groups	Michael Björklund
17.10.2017	Stability of asymptotic representations, cohomology vanishing, and non-approximable groups	Prof. Dr. Andreas Thom

Talks during summer semester 2017
Date	Title	Speaker
04.07.2017	Topology of ends of nonpositively curved manifolds	Grigori Avramidi
23.05.2017	Higher dimensional accessibility and bounding curves on surfaces	Nir Lazarovich
25.04.2017	Holonomy perturbations and irreducible SL(2,C)-representations of homology 3-spheres	Raphael Zentner

Talks during winter semester 2016/17
Date	Title	Speaker
24.01.2017	The notion of positivity in contact geometry (RTG Day)	Prof. Dr. Peter Albers
15.12.2016	Borel equivalence relations and subadditive convergence (RG Topology)	Dr. Felix Pogorzelski
13.12.2016	On entropy theory beyond amenable groups (RTG Day)	Dr. Felix Pogorzelski
24.11.2016	Invariant random subgroups (RG Topology)	Dr. Arie Levit
22.11.2016	Counting commensurability classes of hyperbolic manifolds (RTG Day)	Arie Levit
18.11.2016	Holomorphic line bundles on locally homogeneous complex manifolds (Geometry Day)	Andy Sanders
18.11.2016	On translated points of contactomorphisms (Geometry Day)	Margherita Sandon
18.11.2016	On the linearity of lattices in affine buildings (Geometry Day)	Jean Lécureux
17.11.2016	Topological waist inequalities (AG Topology)	Meru Alagalingam
25.10.2016	Group actions on dendrites (RTG Day)	Dr. Bruno Duchesne

Talks during summer semester 2016
Date	Title	Speaker
14.07.2016	Thurston and Alexander norms, and the Bieri-Neumann-Strebel invariants for free-by-cyclic groups (RG Topology Seminar)	Dr. Dawid Kielak
05.07.2016	Random walks in soluble group theory (GGT-Seminar)	Prof. Dr. Peter H. Kropholler
30.06.2016	tba (RG Topology Seminar)	Prof. Dr. Stefan Friedl
28.06.2016	Simplicial volume of surface bundles and other invariants	Caterina Campagnolo
09.06.2016	Universal L^2-torsion. L^2-Euler characteristics, polytopes and the Thurston norm	Prof. Dr. Wolfgang Lück
31.05.2016	Local-to-Global rigidity for singular spaces (GGT-Seminar)	Dr. Romain Tessera
12.05.2016	Haskell für Mathematiker	Dipl.-Math. Dipl.-Inform. Joachim Breitner

Talks during winter semester 2015/16
Date	Title	Speaker
20.10.2015	C*-simplicity and the amenable radical (GGT-Seminar)	Adrien Le Boudec
19.01.2016	Geometric and analytic aspects of Higgs bundle moduli spaces (GGT-Seminar)	Dr. Jan Swoboda
28.01.2016	On Finiteness Properties of Totally Disconnected Locally Compact Groups	Dr. Werner Thumann
22.10.2015	Strong Novikov conjecture for virtually nilpotent groups	Dr. Alexander Engel

Talks during summer semester 2015
Date	Title	Speaker
23.07.2015	Torus actions and positive curvature in small dimensions	Dr. Lee Kennard
16.07.2015	Simplicial volumes of amenable manifolds	Prof. Dr. Clara Löh
02.07.2015	Kaplansky’s zero-divisor conjecture, the unique product property, and CAT(0) cubulation	Mag. Markus Steenbock
09.06.2015	Positive Scalar Curvature and Stable Homotopy Theory (Abstract)	Prof. Dr. Johannes Ebert
21.05.2015	Beschränkte Kohomologie und partielle Differentialgleichungen	Dr. Andreas Ott

Talks during winter semester 2014/15
Date	Title	Speaker
05.02.2015	Local rigidity and the Farrell-Jones Conjecture	Dr. Holger Kammeyer
20.01.2015	Group actions on Sasakian manifolds (GGT-Seminar)	Prof. Dr. Oliver Goertsches
16.12.2014	Bounded cohomology of acylindrically hyperbolic groups (GGT-Seminar)	Dr. Alessandro Sisto

Talks during summer semester 2014
Date	Title	Speaker
15.07.2014	Bounding lengths of closed geodesics on 3-manifolds with lower curvature bounds (Colloquium)	Prof. Dr. Vitali Kapovitch
22.05.2014	Positive Ricci curvature on highly connected manifolds	Dr. Diarmuid Crowley

Talks during winter semester 2013/14
Date	Title	Speaker
19.11.2013	Geometrie und Dynamik diskreter Untergruppen von halbeinfachen Liegruppen (Colloquium)	Prof. Dr. Anna Wienhard

Talks during summer semester 2013
Date	Title	Speaker
18.07.2013	Topological obstructions to positive curvature and symmetry	Dr. Lee Kennard
09.07.2013	Invariante 4-Formen und symmetrische Räume (Colloquium)	Prof. Dr. Uwe Semmelmann
04.07.2013	An Introduction to Asymptotic Dimension and Decomposition Complexity	Prof. Dr. David Rosenthal
27.06.2013	Uniformly finite homology	Francesca Diana
25.06.2013	Positive Skalarkrümmung: Existenz und Klassifikation (Colloquium)	Prof. Dr. Bernhard Hanke
13.06.2013	Zur Topologie von positiv gekrümmten Mannigfaltigkeiten mit Symmetrien
06.06.2013	The Higgs bundle moduli space and L^2-cohomology	Dr. Jan Swoboda
23.05.2013	The rho-invariant and the local cohomology approach to KO-homology	Dr. Malte Röer
02.05.2013	Some spectral computations of random walk operators - more details	Dr. Łukasz Grabowski
30.04.2013	Some spectral computations of random walk operators (GGT-Seminar)	Dr. Łukasz Grabowski
25.04.2013	From representation spaces to quantum invariants of graphs	Dr. Raphael Zentner
18.04.2013	L2-invisibility and a class of local similarity groups	Werner Thumann

Talks during winter semester 2012/13
Date	Title	Speaker
16.01.2013	Relative Bounded Cohomology	Matthias Blank
15.01.2013	An introduction to Bounded Cohomology	Matthias Blank
10.01.2013	Group actions on compact spaces (Colloquium)	Prof. Dr. Arthur Bartels
31.10.2012	The simplicial volume of manifolds with boundary	Cristina Pagliantini
24.10.2012	Die Farrell-Jones Vermutung für Graph Produkte von Gruppen	Henrik Rüping
17.10.2012	Über L²-Invarianten von Gittern in halbeinfachen Liegruppen	Holger Kammeyer