# Talks since 1996 (Selection)

Title | Conference | Date |
---|---|---|

K- and L-groups of crsystallogrphic groups and applications | Workshop Manifolds and Groups, Oberwolfach | February 2020 |

Die Sprache, die Faszination und die Bedeutung der Mathematik | Brücken in der Mathematik, Münster | Juli 2019 |

Lehmer's problem for arbitrary groups | SFB-seminar, Regensburg | June 2019 |

L^2-Betti numbers and their applications (I, II and III) | Distinguished Lecture series at University of Notre Dame, Notre Dame, U.S.A. | April 2019 |

The stable Cannon Conjecture | 2019 Bloomington Geometry Workshop, Bloomington, U.S.A. | April 2019 |

Introduction to the Farrell-Jones Conjecture | Distinguished Lecture series at Indiana University, Bloomington, U.S.A. | April 2019 |

L^2-Betti numbers and their applications (I and II) | Distinguished Lecture series at Indiana University, Bloomington, U.S.A. | April 2019 |

Universal L^2-torsion, L^2-Euler characteristic, Thurston norm and polytopes | Topology seminar, University of Chicago | March 2019 |

Introduction to 3-manifolds | Topology of manifold: Interactions between high and low dimensions, Matrix Institute, Parkville, Australia | January 2019 |

Introduction to hyperbolic groups | Topology of manifold: Interactions between high and low dimensions, Matrix Institute, Parkville, Australia | January 2019 |

Topological rigidity | Topology of manifold: Interactions between high and low dimensions, Matrix Institute, Parkville, Australia | January 2019 |

L^2-invariants | January 2019 | |

The stable Cannon Conjecture | January 2019 | |

The stable Cannon Conjecture | Workshop: Manifolds, Program: Homotopy harnessing higher structures, Isaac Newton Institute, Cambridge | December 2018 |

Classifying spaces for families and the Farrell-Jones Conjecture | Colloquium on the occasion of tom Dieck's 80th birthday, Göttingen | November 2018 |

Universal L^2-torsion, L^2-Euler characteristic, Thurston norm and polytopes | SMS-DMV Workshop: Spectra and L2-invariants, Geneva | September 2018 |

The stable Cannon Conjecture | Workshop Topology, Oberwolfach | July 2018 |

The stable Cannon Conjecture | Workshop on Large Scale Geometry and Applications, Fields Institute, Toronto | May 2018 |

Introduction to L^2-invariants | Inaugural Colloquium of the Thematic program "L2-invariants and their analogues in positive characteristic", Madrid | February 2018 |

Hyperbolic groups with spheres as boundary and a stable version of the Cannon Conjecture | Conference "manifolds and groups", Regensburg | September 2017 |

Survery on The Farrell-Jones Conjecture and its application | Workshop: K-theory in topology and non commutative geometry, TP K-Theory and Related Fields HIM, Bonn | August 2017 |

Aspherical manifolds, what we know and what we do not know | Colloquium, Augsburg | May 2017 |

The Farrell-Jones Conjecture and its application | Seminar, Paris 7 | March 2017 |

Aspherical manifolds, what we know and what we do not know | Colloquium, Freiburg | November 2016 |

The group cohomology of certain crystallographic groups and applications | Workshop: The Farrell-Jones conjecture, JTP Topology HIM, Bonn | October 2016 |

Universal L^2-torsion, Twisted L^2-Euler characteristic, Thurston norms and polytopes | Workshop: New directions in L2-invariant, JTP Topology HIM, | October 2016 |

Universal L^2-torsion, Twisted L^2-Euler characteristic, Thurston norms and polytopes | Conference Measured Topology, Oberwolfach | August 2016 |

The Farrell-Jones Conjecture for Waldhausen's A-theory, automorphism groups of aspherical manifolds, and approximately fibering manifolds | Conference: Topology of manifolds (Michael Weiss' 60th birthday) , Lisbon | June 2016 |

Survey on L^2-invariants | Conference: Algebra in Geometry (Erik Pedersen 70th birthday) , Copenhagen | June 2016 |

Introduction to L^2-Betti numbers | Colloquium, Fribourg (Switzerland) | June 2016 |

L^2-Euler characteristics and the Thurston norm | Geometric Topology Seminar, MPI for Mathematics, Bonn | April 2016 |

The group cohomology of certain crystallographic groups and applications | Conference Topological and Homological Methods in Group Theory Topology Seminar, Bielefeld | April 2016 |

Universal torsion, L2-invariants, polytopes and the Thurston norm | Topology Seminar, Münster | December 2015 |

Introduction to L^2-Betti numbers | Colloquium, Düsseldorf | November 2015 |

Survey on L^2-invariants | BICMR-HCM: Beijing meets Bonn | November 2015 |

Aspherical manifolds, what we know and what we do not know | Clay Research Conference Algebraic Topology: manifolds unlocking higher structures, Oxford | September 2015 |

Survey on L^2-torsion | Workshop Manifolds and Groups, Ventotene | September 2015 |

Universal torsion, L^2-invariants, polytopes and the Thurston norm | PIMS Symposium on the Geometry and Topology of Manifolds, Vancouver | July 2015 |

Introduction to the Farrell-Jones Conjecture | PIMS Symposium on the Geometry and Topology of Manifolds, Vancouver | July 2015 |

Universal torsion, L^2-invariants, polytopes and the Thurston norm | The 32nd Annual Workshop in Geometric Topology, Fort Worth | June 2015 |

Introduction to the Farrell-Jones Conjecture | The 32nd Annual Workshop in Geometric Topology, Fort Worth | June 2015 |

Introduction to L^2-invariants | The 32nd Annual Workshop in Geometric Topology, Fort Worth | June 2015 |

Introduction to the Farrell-Jones Conjecture | Colloquium, Bayreuth | June 2015 |

Introduction to the Farrell-Jones Conjecture I + II | Follow workshop Rigidity, HIM, Bonn | April 2015 |

Universal torsion, L^2-invariants, polytopes and the Thurston norm | Conference Asymptotic Invariants of Groups, Oxford | April 2015 |

K-theory of group algebras and topological cyclic homology | Conference Homotopy Theory, Oberwolfach | March 2015 |

Introduction to homology and L^2-cohomology | Kolloquium, Dresden | February 2015 |

Universal L^2-torsion, Twisted L^2-Euler characteristic, Thurston norm and higher order Alexander polynomials | Conference Geometric Topology, Oberwolfach | January 2015 |

Was und wie zählt man im Alltag und in der modernen Mathematik? | Kolloquium zur Didaktik der Mathematik, Karlsruhe | December 2014 |

Introduction to L^2-cohomology | Colloquium, Warrick | November 2014 |

Hyperbolic groups with spheres as boundary | Geometry and Topology Seminar, Warrick | November 2014 |

Homological methods in mathematics | Programm DEMAIN -Workshop, Münster | September 2014 |

The twisted L^2-torsion function and its application to $3$-manifolds | Conference Topology, Oberwolfach | September 2014 |

The twisted L^2-torsion function and its application to $3$-manifolds | Conference Low-dimensional Topology and Number Theory, Oberwolfach | August 2014 |

Was und wie zählt man im Alltag und in der modernen Mathematik? | Kolloquium über Didaktik Geschichte und Didaktik der Mathematik, Münster | June 2014 |

From the classification of Cuntz-Li-C^*-algebras to the cohomology of crystallographic groups | Oberseminar Topology, Göttingen | June 2014 |

L^2-Invariants, their applications and open problems | Oberseminar Globale Analysis, Regensburg | May 2014 |

Survey about L^2-Invariants and their applications | colloquium, Augsburg | May 2014 |

Introduction to the Farrell-Jones Conjecture | topology seminar, Augsburg | May 2014 |

Algebraic K- and L-theory of groups rings and their applications to topology and geometry | NRW topology meeting, Wuppertal | May 2014 |

What are the possible values of L^2-Betti numbers | topology seminar, Edinburgh | April 2014 |

Introduction to L^2-invariants | colloquium, Edinburgh | April 2014 |

Algebraic K- and L-theory of groups rings and their applications to topology and geometry | topology seminar in Berkey | April 2014 |

Introduction to the middle K-theory of group rings and their relevance in topology | topology seminar in Berkey | April 2014 |

Was und wie zählt man im Alltag und in der modernen Mathematik? | Felix-Hausdorff-Vorlesung im Alfried Krupp Wissenschaftskolleg Greifswald | January 2014 |

Heat kernels and their applications in geometry, topology and group theory. | Bethe Kolloquium of Institute for Physics in Bonn | January 2014 |

Survey on open problems about L^2-invariants: Atiyah's Question, Singer's conjecture, homological growth and Lehmer's problem for arbitrary groups | Topology Oberseminar, Münster | December 2013 |

L^2-invariant and homological growth | Seminar Homology Growth in Geometry and Arithmetic at MPI in Bonn | November 2013 |

Introduction to L^2-invariants | Seminar Homology Growth in Geometry and Arithmetic at MPI in Bonn | November 2013 |

Survey on L^2-invariants | Colloquium of the Department of Mathematics of the Columbia University, New York | October 2013 |

Hyperbolic groups with spheres as boundary | CUNY, New York | October 2013 |

Introduction to the Farrell-Jones Conjecture | Colloquium of the Courant Institute, New York | October 2013 |

Hyperbolic groups with spheres as boundary | Conference Geometry, Groups and Topology 2013, Karlsruhe | October 2013 |

K_0 and Wall's finiteness obstruction, Lecture I | Topology of high-dimensional manifolds, Summer School in Bonn | August 2013 |

K_1 and Whitehead torsion, Lecture II | Topology of high-dimensional manifolds, Summer School in Bonn | August 2013 |

The Isomorphism Conjectures in the torsionfree case, Lecture III | Topology of high-dimensional manifolds, Summer School in Bonn | August 2013 |

The Isomorphism Conjectures in general, Lecture IV | Topology of high-dimensional manifolds, Summer School in Bonn | August 2013 |

Status and Methods of Proof, Lecture V | Topology of high-dimensional manifolds, Summer School in Bonn | August 2013 |

Approximation L^2-invariants and homological growth | Conference Group theory, Measure, and asymptotic invariants, topology and geometry, Oberwolfach | August 2013 |

Survey on L^2-invariants | Colloquium, Leibzig | July 2013 |

On the Farrell-Jones Conjecture | Colloquium, Berlin | July 2013 |

Fulgede-Kadison determinants and L^2-torsion | Conference Growth and Mahler measure in geometry and topology, Mittag-Leffler Institute, Djursholm, Sweden | July 2013 |

From the classification of Cuntz-Li-C^*-algebras to the cohomology of crystallographic groups | Geometric Structures in Group Theory, Oberwolfach | June 2013 |

Survey on Isomorphism Conjectures | SYM lecture, Copenhagen | May 2013 |

Survey on L^2-invariants | Colloquium, Copenhagen | May 2013 |

Survey on L^2-invariants | 20-th anniversary of ESI, Erwin-Schrödinger Institut, Vienna | April 2013 |

From the classification of Cuntz-Li-C^*-algebras to the cohomology of crystallographic groups | MPI Oberseminar, Bonn | February 2013 |

Homological growth and L^2-invariants | Hirzebruch Lecture Münster | December 2012 |

L^2-invariants and applications to group theory | Cohomological Methods in Geometric Group Theory, Banff | November 2012 |

Motivating the Farrell-Jones Conjecture | Topology, Oberwolfach | September 2012 |

Homological growth and L^2-invariants | Low-Dimensional Topology and Number Theory, Oberwolfach | August 2012 |

Status and Methods of Proof | Topology and Groups, Summerschool, Berlin | June 2012 |

The Isomorphism Conjectures in general | Topology and Groups, Summerschool, Berlin | June 2012 |

The Isomorphism Conjectures in the torsionfree case | Topology and Groups, Summerschool, Berlin | June 2012 |

Lower and middle K-theory | Topology and Groups, Summerschool, Berlin | June 2012 |

L^2-Betti numbers their applications | Joint colloquim Marburg and Gießen, Marburg | June 2012 |

L^2-approximation and homological growth | Topology Oberseminar, Münster | January 2012 |

L^2-approximation and homological growth | Conference Stratified Spaces: joining analysis, topology and geometry, Oberwolfach | December 2011 |

On the Farrell-Jones Conjecture | Sektion Geometrie-Topologie, DMV-Jahres-Tagung in Köln | September 2011 |

Approximating in prime characteristic | Workshop L^2 invariants and their relatives for finitely generated groups at AIM in Palo Alto | September 2011 |

Approximating the first L^2-Betti number of residually finite groups | Topology Seminar at Münster | July 2011 |

The flow space associated to a CAT(0)-space | Summer school Geodesic Flow, Negative Curvature and Isomorphism Conjectures in Göttingen | June 2011 |

Strategy of proof: From Farrell-Jones to flow spaces | Summer school Geodesic Flow, Negative Curvature and Isomorphism Conjectures in Göttingen | June 2011 |

The Farrell-Jones Conjecture | Summer school Geodesic Flow, Negative Curvature and Isomorphism Conjectures in Göttingen | June 2011 |

Introduction to Algebraic K-theory | Summer school Geodesic Flow, Negative Curvature and Isomorphism Conjectures in Göttingen | June 2011 |

Approximation of L^2-torsion and homological growth | Conference Finite Approximations of discrete groups, Oberwolfach | May 2011 |

An introduction to the Farrell-Jones Conjecture | Conference New directions in algebraic K-theory, Oberwolfach | May 2011 |

Approximating L^2-torsion and homological growth | Oberseminar Global Analysis in Bonn | December 2010 |

Constructing infinite, finitely generated, residually finite torsion groups with positive first L^2-Betti number | Oberseminar Topology in Bonn | December 2010 |

On the Farrell-Jones Conjecture and its applications | Conference K-theory, C*-algebras, index theory in Göttingen | November 2010 |

Approximating l^2-invariants by their finite dimensional ananalogues | Kolloquium Bonn | October 2010 |

K- and L-theory of group rings | Topology section, ICM 2010, Hyderabad | August 2010 |

On hyperbolic groups with spheres as boundary | Kolloquium Heidelberg | July 2010 |

On hyperbolic groups with spheres as boundary | The Third GAF-conference Group actions in Topology and Geometric Group Actions in Poznan | June 2010 |

On hyperbolic groups with spheres as boundary | Kolloquium Osnabück | June 2010 |

The Farrell-Jones Conjecture for hyperbolic and CAT(0)-groups | Conference Non-positive curvature and geometric structures in group theory, Oberwolfach | April 2010 |

Lebendige Mathematik, auch abseits des Lehrplans? | 101. MNU Bundeskongress 2010, Bielefeld | March 2010 |

On hyperbolic groups with spheres as boundary | Copenhagen Topology Conference | January 2010 |

On hyperbolic groups with spheres as boundary | Kolloquium Bonn / Workshop: Rigidity in cohomology, K-theory, geometry and ergodic theory at the HIM in Bonn | November 2009 |

Introduction to and new results about the Farrell-Jones Conjecture | Oberseminar Topologie, Bonn | November 2009 |

Warum bin ich eigentlich Mathematiker geworden ? | 3. Bildungskongress Münster: Individuelle Förderung multipler Begabungen, Münster | September 2009 |

Das Chamäleon Mathematik | Nordrhein-Westfälische Akademie der Wissenschaften und der Künste, Düsseldorf | September 2009 |

Introduction to the Farrell-Jones Conjecture | Summerschool Geometry and Rigidity of groups at Münster | August 2009 |

Topologische Starrheit | Kolloquium (Wilhelm Singhof's sixtieth birthday) , Düsseldorf | July 2009 |

Introduction to the Farrell-Jones Conjecture | Focused semester on K-theory, Münster | June 2009 |

Die Sprache, die Faszination und die Bedeutung der Mathematik | Kolloquium Geschichte und Didaktik der Mathematik, Münster | June 2009 |

On the Borel Conjecture and related topics | Conference on manifold pespectives, Oberwolfach | May 2009 |

L^2-torsion, Whitehead groups and group automorphisms | Oberseminar Globale Analysis, Bonn | April 2009 |

On the Borel Conjecture and related topics | Ferry Fest, Chicago | March 2009 |

Die Farrell-Jones-Vermutung und ihre Anwendungen | Göttingen | February 2009 |

K- and L-theory von Gruppenringen und topologische Starrheit | Colloquium, Hamburg | January 2009 |

Topological Rigidity | BMS-Friday, Berlin | November 2008 |

Die Sprache, die Faszination und die Bedeutung der Mathematik | Veranstaltung zum Jahr der Mathematik, Bremen | November 2008 |

Die Sprache, die Faszination und die Bedeutung der Mathematik | Herbstforum 2008, Lüdinghausen | November 2008 |

Topologische Starrheit | Colloquium, Bochum | November 2008 |

K- and L-theory von Gruppenringen und topologische Starrheit | Colloquium, Paderborn | November 2008 |

K- and L-theory of group rings and topological rigidity | Conference ``Von Neumann algebras and ergodic theory of group actions´´, Oberwolfach | October 2008 |

K- and L-theory of group rings and topological rigidity | Colloquium, Regensburg | October 2008 |

On the Borel Conjecture and related topics | ''Analytic properties of infinite groups'', conference , Geneva | August 2008 |

On the topological rigidity of aspherical manifolds | 5-th European Congress of Mathematics, invited lecture, Amsterdam | July 2008 |

Die Sprache, die Faszination und die Bedeutung der Mathematik | Veranstaltung zum Jahr der Mathematik und zum 60. Geburtstag von Andrew Ranicki, Münster | June 2008 |

Topological rigidity | Colloquium de Mathematiques, Jussieu, Paris | May 2008 |

On the conjectures of Bost and of Baum-Connes and the generalized trace conjecture | Seminar operator algebras, Jussieu, Paris | May 2008 |

On the Borel Conjecture and related topics | ``Singularities in geometry and topology'', in honor of Cappell's syitieth birthday, Courante Institut, New York | March 2008 |

The Burnside ring, equivariant homotopy and the Segal Conjecture for infinite groups | 2008 Spring Eastern Meeting New York, | March 2008 |

On the Borel Conjecture and related topics | Topology seminar, Berkeley | March 2008 |

On the Borel Conjecture and related topics | Kolloquium, Stanford | February 2008 |

The mystery of aspherical closed manifolds | Kolloquium, Bonn | November 2007 |

On the conjecture of Novikov and Borel | Seminar des MPI Bonn, Bonn | October 2007 |

The Burnside ring, equivariant homotopy and the Segal Conjecture for infinite groups | Conference ``homotopy theory´´, Oberwolfach | September 2007 |

Isomorphism Conjecture in K- and L-theory (six lectures) | ``Cohomology of groups and algebraic K_theory´´, international summer school in Hangzhou, China | July 2007 |

The K-theoretic Farrell-Jones Conjecture for hyperbolic groups | Feier zum 90. Geburtstag von Beno Eckmann, ETH Zürich | April 2007 |

The Farrell-Jones Conjecture and its applications | Oberseminar Topologie, Bonn | April 2007 |

The Farrell-Jones Conjecture and its applications | Conference ``Lauch meeting for the journal of topology´´, Oxford | March 2007 |

Topological rigidity for non-aspherical manifolds | Conference ``Topology´´, Banff | February 2007 |

Equivariant Chern characters | Göttingen | November 2006 |

Erfahrungen eines Hochschullehrers mit dem Lehramtsstudium | Minisymposium Lehrerausbildung DMV-Tagung Bonn | September 2006 |

The Farrell Conjecture for algebraic K-theory with arbitrary coefficients for word-hyperbolic groups | ICM06 Satellite on ``K-theory and Noncommutative Geometry´´, Valladolid | September 2006 |

Equivariant homology theory and assembly maps | Conference ``Surgery theory: past, present and future´´, Edinburgh (Wall's 70-th birthday) | July 2006 |

Burnside rings, equivariant homotopy and the Segal Conjecture for infinite groups | Workshop ''Prospects in topology'', Münster | June 2006 |

Burnside rings, equivariant homotopy and the Segal Conjecture for infinite groups | Topology seminar at the Mittag-Leffler institute, Stockholm | May 2006 |

The algebraic K-theory of the group ring of a word hyperbolic group with arbitrary coefficient ring | Conference ``Topological and geometric methods in group theory´´, Oberwolfach | April 2006 |

Isomorphism Conjectures in algebraic K- and L-theory and topological rigidity | ``25-th anniversary of MPIM´´, MPIM Bonn | April 2006 |

The Farrell Conjecture for algebraic K-theory with arbitrary coefficients for word-hyperbolic groups | Conference ``Analysis and Topology in interaction´´, Oberwolfach | March 2006 |

From finite groups to infinite groups | Conference ``Cohomology of finite groups - Interactions and applications´´, Oberwolfach | September 2005 |

L^2-invariants and applications | Conference ``Topology´´, Banff | August 2005 |

How to compute K- and L-groups of group rings of infinite groups | Conference ``Algebraic K- and L-theory of infinite groups´´, Edinburgh | June 2005 |

Klassifizierende Räume von Familien von Untergruppen | Kolloquium des Fachbereichs Mathematik der Universität Mainz | June 2005 |

The Baum-Connes Conjecture, trace maps and Chern characters | Geometrie-Seminar des Fachbereichs Mathematik der Universität Köln | June 2005 |

L^2-cohomology and geometric group theory | Mathematische Arbeitstagung June 10-16 2005, Max-Planck-Institut für Mathematik, Bonn | June 2005 |

Topologische Starrheit für nicht asphärische Mannigfaltigkeiten | Kolloquium der Fachgruppe Mathematik der Universität Bonn | June 2005 |

Middle algebraic K-theory of von Neumann algebras, group C^*-algebras and group rings | Conference ``Non-commutative geometry and operator algebras´´, Nashville | May 2005 |

The Baum-Connes Conjecture, trace maps and Chern characters | Colloquium of the MPI for Mathematics, Bonn | April 2005 |

Rational Computations of the Topological K-Theory of Classifying Spaces of Discrete Groups | NRW-topology meeting, Bochum | April 2005 |

Survey on L²-invariants | Imperial College, London | November 2004 |

Survey on classifying spaces | Southampton | November 2004 |

Equivariant Chern characters and applications to K- and L-theory | Edinburgh | November 2004 |

Equivariant Chern characters and applications to K- and L-theory | Conference ``Noncommutative geometry´´, Oberwolfach | September 2004 |

Isomorphism Conjectures in K- and L-theory | 40-th anniversary of the FIMS at the ETH, Zürich | July 2004 |

A Survey on the Baum-Connes Conjectures | giornata INdAM, Rome | June 2004 |

A panorama on L²-invariants and their applications | SUP-Symposium Oslo | May 2004 |

Klassifizierende Räume von Familien | Colloquium, International University of Bremen | November 2004 |

Rational injectivity of the Farrell-Jones assembly map for algebraic K-theory | Geometry and analysis on manifolds (Dan Burghelea's sixtieth birthday), Columbus | March 2004 |

Computations of K-and L-groups of group rings and C^*-algebras | Conference ``Topology of manifolds and homotopy theory´´, Banff, | March 2004 |

L²-cohomology | Conference ``von Neumann algebras´´, C.I.R.M Luminy, | February 2004 |

L²-Invariants | Geometry and Cohomology in Group Theory, LMS Durham Symposium, Durham | July 2003 |

Chern characters and applications to K- and L-theory | International Conference on Group Theory: combinatorial, geometric and dynamical aspects of infinite groups in Gaeta (Italy) | June 2003 |

Equivariant Chern characters and application to K- and L-theory | Conference ``Algebraic K-theory and its applications´´, Trieste, | July 2002 |

Equivariant Chern characters and application to K- and L-theory | Aarhus topology conference 2002 | June 2002 |

Vortragsreihe: ``L²-invariants´´ | Borel Seminar in Bern | April 2002 |

Vortragsreihe: ``L²-invariants´´ | Conference/School in Lyon | October 2001 |

The relation between the Baum-Connes Conjecture and the trace conjecture | Conference ``High-dimensional manifold theory´´, Trieste | June 2001 |

Vortragsreihe: ``Introduction to surgery'' | School in Trieste | June 2001 |

`Equivariant Chern characters | Festkolloquium zu Mislin's 60. Geburtstag | April 2001 |

The relation between the Baum-Connes Conjecture and the trace conjecture | Conference ``Topological methods in group theory´´ in Oberwolfach | January 2001 |

Equivariant Chern characters | Conference ``Algebraic topology´´, Barcelona | July 2000 |

Computing the source of the assembly map' | Conference ``Noncommutative geometry´´ in Oberwolfach | March 2000 |

Survey on L²-invariants | Conference ``L²-methods and K-theory´´ in Oberwolfach | September 1999 |

L²-invariants and singular spaces | Conference ``From manifolds to singular varieties´´, Boulder | June 1999 |

Dirac operators and index theory | Conference ``Dirac operators and Spin geometry´´, Oberwolfach | April 1999 |

Isomorphisms Conjectures in K-and L-theory and computations for certain crystallographic groups | Workshop ``Stable homotopy theory and algebraic K-theory´´, Bielefeld | February 1999 |

L²-Betti numbers and dimension functions | Conference ``Geometry and topology'', Aarhus | August 1998 |

The completion theorem in K-theory for proper actions of a discrete group | Conference ``Algebraic topology´´, Barcelona | June 1998 |

Generalized Novikov-Shubin invariants | Conference ``Topology'', Tel Aviv | June 1998 |

Spectra over a category and isomorphism conjectures of Baum-Connes and Farrell-Jones I, II and III | Workshop ``K-homology of classifying spaces and K-theory of C*-algebras´´, Les Diablerets (Schweiz) | March 1998 |

The completion theorem in K-theory for proper actions of a discrete group | Conference ``Group actions on manifolds´´, Oberwolfach | February 1998 |

Dimension functions over finite von Neumann algebras and applications to L²-Betti numbers | Conference ``Prospects in geometry´´, Leipzig | November 1997 |

Reidemeister torsion und L²-torsion | Seifert-Colloquium in Heidelberg | October 1997 |

L²-Torsion | Conference ``Algebraic topology´´, Kazimierz (Polen) | July 1997 |

Dirac operators and Spin geometry | Workshop on ``Dirac operators on loop spaces´´, Oberwolfach | June 1997 |

Dimension functions over finite von Neumann algebras and applications to L²-Betti numbers | Eckmann-Colloquium in Zürich | April 1997 |

Analytic theory of the Dirac operator I, II and III | Conference ``Dirac operator and geometry´´, Warschau | February 1997 |

Reidemeister Torsion und analytische Torsion | Franz-Colloquium, Heidelberg | November 1996 |

L²-Invarianten von Mannigfaltigkeiten und Gruppen | DMV-Tagung in Jena | September 1996 |

L²-torsion | Conference ``Topology and analysis on singular spaces´´, Oberwolfach | June 1996 |