Invited by

June 13, 2024

Large audience talk “Sistemas Dinámicos y geométricos de grupos”, Universidad Andina del Cusco, Peru

George Luis Aguilar Villafuerte

September 28, 2023

Talk at the conference ComPer23,  Purdue University, Indiana “New tools for studying the topology of bacterial protein interaction networks”

Tao Hou

September 21, 2023

Talk at the 4th Workshop on Topological Methods in Data Analysis, Universität Heidelberg:

“Persistent Maximum of Loops in Bacterial Protein Interaction Networks”

Freya Jensen

July 12, 2023

Invited talk at University of Luxembourg: Torsion in the cohomology of special linear groups over the natural integers

Gabor Wiese

June, 27- June 30, 2022

Talk at the Workshop on Cohomology, Geometry and Explicit Number Theory  (preceded by a a summer school), Institut Fourier Grenoble: “Verification of the Quillen conjecture in the rank 2 imaginary quadratic case”

 The Cohomology, Geometry and Explicit number theory (COGENT) consortium

October 3-8, 2021

Talk at the Banff International Research Station workshop Lattices and Cohomology of Arithmetic Groups: Geometric and Computational Viewpoints: “On Farrell-Tate cohomology of GL(3) over rings of quadratic integers”

Paul Gunnells,

Philippe Elbaz-Vincent,

Graham Ellis

June 5, 2019

Invited talk in the Wuppertal Topology Seminar. “Computing the 2-torsion in the cohomology of PSL(4,Z)”

Matthias Wendt

May 17, 2019

Talk at the Computeralgebra-Tagung 2019 in Kassel, Germany. “Computer Algebra implementations and applications to cohomology of groups, equivariant K-homology, Chen-Ruan orbifold cohomology”

Wolfram Koepf

25-29 March, 2019

Invited talk at the conference Cohomology of Arithmetic Groups, Lattices and Number Theory: Geometric and Computational Viewpoint at Centre International de Rencontres Mathématiques (CIRM), Luminy, France.

Bayer, Elbaz-Vincent, Ellis, Gunnells

October 17, 2018

Invited talk in the Oberseminar Geometrie, University of Fribourg (Swiss Confederation): Hyperbolic orbifolds and their twisted sectors

Ruth Kellerhals

17-21 Sep. 2018

GAP days, University of Siegen, Germany, talk “The Rigid Facets Subdivision Algorithm in GAP”.

Mohamed Barakat, Max Horn

11-14 Sep. 2018

Dragon Applied Topology Conference, at the Department of Mathematics, University of Swansea, UK.

Jeffrey H. Giansiracusa

June 6, 2018

Colloquium of the mathematics institute, TU Kaiserslautern, Germany

Wolfram Decker

12-16 Feb. 2018

Invited talk at the workshop K-theory, A1 homotopy and quadratic forms at Mathematics Institute, University of Warwick, UK

Marco Schlichting

23 Jan. 2018

Invited talk at the Séminaire Algèbre-Géométrie of Laboratoire de Mathématiques de Versailles, France

Dimitri Zvonkine

8-9 December 2017

Talk at the international conference on group and representation theory "Nikolaus conference 2017" of Lehrstuhl D für Mathematik at RWTH Aachen

Frank Lübeck

19-23 June 2017

Invited talk at the 8th Atelier PARI/GP at Laboratoire de mathématiques Blaise Pascal, Clermont-Ferrand, France.

Bill Allombert

2-16 June 2017

Invited participation at the LMFDB workshop Classical, Hilbert and Bianchi Modular Forms, their L-functions and Galois representations at Mathematics Institute, University of Warwick, UK.

John Cremona

May 11th, 2017

Seminar talk in the Mathematische Gesellschaft of the Mathematisches Institut der Universität Göttingen

Claudia Schoemann

April 11th, 2017

Seminar talk at the Institut de Recherche Mathématique Avancée (IRMA) Strasbourg, on "Cohomology of arithmetic groups and the Quillen conjecture"

Hans-Werner Henn, Gael Collinet

30 Oct - 5 Nov 2016

Talk at the workshop Computations in the Cohomology of Arithmetic Groups at Mathematisches Forschungsinstitut Oberwolfach (MFO)

Eva Bayer-Fluckiger, Philippe Elbaz-Vincent, Graham Ellis

June 6-8, 2016

Talk at the joint Conference of the Belgian, Royal Spanish and Luxembourg Mathematical Societies, in Logroño, La Rioja

Gabor Wiese

October 19, 2015

Talk at Universitaet Giessen, Germany : Ruan's cohomological crepant resolution conjecture Universitaet Giessen

Ralf Köhl

Sept. 28 to October 2, 2015

Talk at the conference of the DFG priority project SPP 1489, Algorithmic & Experimental Methods in Algebra, Geometry and Number Theory, at Universitaet Osnabrueck, Germany

Winfried Bruns

Aug. 31-Sept. 3, 2015

Talk at the conference "Finiteness Conditions in Topology and Algebra", at Queen's University Belfast (UK)

Thomas Hüttemann

July 29th, 2015

Seminar talk at IST Austria (Institute of Science and Technology), Software for hyperbolic geometry and applications to isometry groups

Herbert Edelsbrunner

July 15, '15

Seminar Gruppen, Geometrie, Dynamik of Universitaet Giessen

Ralf Koehl

June 15th to 20th, 2015

Talk at the conference DyToComp 2015 - Dynamics, Topology and Computations, Mathematical Research and Conference Center in Bedlewo, Poland, A software for computations on the Dynamics and Topology of the Bianchi groups

Piotr Zgliczyński

April 29th, 2015

Algebra Seminar, University of Glasgow, From a question of Serre to the Quillen-Wendt conjecture

Luigi Vergori

April 2nd, 2015

Seminar of the research group Arithmétique et Théorie de l'Information (ATI),Luminy, Méthodes cohomologiques pour les formes modulaires de Bianchi

David Kohel

March 20th, 2015

Pure Mathematics Colloquium of the University of Southampton, Bredon homology calculation techniques

Ruben Sanchez-Garcia

January 12 to 16, 2015

Atelier PARI/GP 2015, Université de Bordeaux, Bianchi groups computation with PARI

Bill Allombert, Karim Belabas

December 1 to 5, 2014

7th de Brun Workshop on Homological Perturbation Theory, From Homological Perturbation Theory to the Quillen-Wendt conjecture

Graham Ellis

July 14 to 16, 2014

Workshop on Bianchi and Siegel modular forms, Sheffield, Bianchi modular forms of varying discriminant, level and weight

Tobias Berger

July 10, 2014

Seminar on Euler Systems/Arithmetic Geometry, U. Duisburg-Essen, The image of the Borel-Serre bordification in algebraic K-theory

Oliver Bräunling

Apr.14,'14

Université de Neuchâtel, Un accès à l'homologie de Bredon

Alain Valette

Dec. 20, 2013

Universitaet Giessen, Germany, Determination of torsion invariants of arithmetic groups Universitaet Giessen

Ralf Koehl

July 19, 2013

Seminar of the Institute of Physics and Mathematics at Universidad Austral de Chile (UACh), Valdivia, Group Actions and Orbit Spaces

Rodrigo Vargas

April 11, 2013

Séminaire Algèbre et topologie, IRMA Strasbourg, Calculs efficaces au dessus de la dimension cohomologique virtuelle

Christine Vespa

Dec. 20, 2012

Séminaire du laboratoire LSIIT Strasbourg, Homologie calculatoire de groupes modulaires

Pascal Schreck, Mohamed Tajine

December 7, 2012

6th de Brún Workshop « Linear Algebra and Matrix Theory: connections, appl. and computations »,  A new technique to extract invariants of matrix groups

Niall Madden, Rachel Quinlan

July 1 to 6, 2012

Banff International Research Station for Mathematical Innovation and Discovery, Canada, talk at the workshop Torsion in the homology of arithmetic groups: geometry, arithmetic, and computation

Paul Gunnells

Jun.4, ‘12

Vrije Universiteit Amsterdam, The arithmetics of symmetric space

Rob de Jeu

February 2012

University College Dublin, Torsion subcomplex reduction and conjugacy classes graphs

Kevin Hutchinson

Feb. 2012

Univ. Freiburg, Reduktion von Torsionsunterkomplexen & Konjugiertenklassengraphen

Matthias Wendt

Nov. 2011

Technische Universität Darmstadt, Polyhedral models for arithmetic groups

Michael Joswig

November 2011

Seminar on Representation Theory and Algebraic Geometry, W.I.S., Number-theoretic formulae for the homological torsion of the Bianchi groups

Dmitry Gourevitch

Oct. 2011

Hebrew University of Jerusalem, Amitsur Algebra seminar, Stringy orbifolds

Alex Lubotzky

July 2011

London Mathematical Society - EPSRC Durham Symposium Geometry and Arithmetic of Lattices, Durham (England), Implications of hyperbolic geometry to operator K-theory of artihmetic groups

Mikhail Belolipetsky

March 2011

GdT. Géométrie hyperbolique et surfaces de Riemann, Univ. Paris 7, Inst. Math. Jussieu, La torsion homologique de SL_2 d'anneaux d'entiers

Nicolas Bergeron

February 2011

Séminaire Algèbre et topologie, IRMA Strasbourg, Modèles cellulaires pour des groupes arithmétiques

Hans-Werner Henn

February 2011

Séminaire Théorie des Nombres de Bordeaux, La conjecture de Baum/Connes - un accès explicite

Guilhem Castagnos

December 2010

Seminar on Representation Theory and Algebraic Geometry, W.I.S., (Co)homologies and K-theory of Bianchi groups using computational models

Stephen Gelbart

November 2009

National University of Ireland at Galway, The integral homology of PSL_2 of imaginary quadratic integers with non-trivial class group

Graham Ellis

November 2009

Séminaire Algèbre et Géométries, Grenoble,Domaines fondamentaux pour groupes de matrices sur des entiers quadratiques imaginaires

Alessandro Chiodo

October 2009

Conférence de l'Institut Fourier, Autrans, Homologie de groupes discrets d'isométries de l'espace hyperbolique

Michel Brion

September 2009

17th ÖMG Congress and Annual DMV Meeting, Graz, Austria, The integral homology of PSL_2 of imag. quad. int. of class number two

Joachim Schwermer

June 2009

Alg., Géom. Alg., Top. Alg., I3M Montpellier, Homologie à coefficients entiers de PSL_2 sur des anneaux d'entiers quadratiques imaginaires

Nicolas Ressayre

June 2009

Research Seminar Comp. Algebra & Number Theory, Düsseldorf, The integral homology of PSL_2 of imaginary quadratic integers

Fritz Grunewald

June 2009

Séminaire de Théorie des Nombres de Montpellier

Louise Nyssen

November 2008

Autumn School about Geometric invariants of groups, Göttingen

Homology of isometry groups of Hyperbolic Space

Andreas Thom

June 2007

Summer School in Algebraic Topology, Univ. Lille, France Characteristic classes of complexified bundles

Sadok Kallel

September 2006

Conference Young Topologists and New Topology at the Banach Math. Center, Bedlewo, Poland, Characteristic classes of real generator bundles

Thomas Schick

2006

Séminaire Gaston Darboux, I3M Montpellier, Variétés pseudoriemanniennes et réductions de fibrés principaux

Philippe Elbaz-Vincent

2006

Math. Institut, Universität Tübingen, The Lefschetz hyperplane intersection theorem

Victor Batyrev