Roman Sauer

Dr. Roman Sauer
Mathematisches Institut
Westfälische Wilhelms-Universität Münster
Einsteinstr. 62
48149 Münster

Tel: ++49(0)251/83 33740
Fax: ++49(0)251/83 38370
sauerr@uni-muenster.de
www.romansauer.de

[Publications] [Teaching] [Conferences] [Talks]

Teaching

Teaching in SS 2010:

Seminar zur geometrischen Gruppentheorie (zusammen mit Michael Joachim) [Programm]
Oberseminar: Perkolation und L²-Bettizahlen (zusammen mit Nina Gantert und Wolfgang Lück) [Programm]

All courses and seminars

Publications

Research papers:

Finiteness obstructions and Euler characteristics of categories
joint with Tom Fiore and Wolfgang Lück
[arXiv:0908.3417]
Spectral distribution and L²-isoperimetric profile of Laplace operators on groups
joint with Alexander Bendikov and Christophe Pittet
[arXiv:0901.0271]
L²-torsion, the measure-theoretic determinant conjecture, and uniform measure equivalence
joint with and Wolfgang Lück and Christian Wegner
[arXiv:0903.2925]
A spectral sequence to compute L²-Betti numbers of groups and groupoids
joint with Andreas Thom
accepted for Journal of the London Mathematical Society.
see also these slides of a talk on this subject.
[arXiv:0707.0906]
Degree theorems and Lipschitz simplicial volume for non-positively curved manifolds of finite volume
joint with Clara Löh
appeared in Journal of Topology, Volume 2, Number 1, 2009
[arXiv:0710.1635] [Journal] [MR2499443]
Simplicial Volume of Hilbert modular varieties
joint with Clara Löh
appeared in Commentarii Mathematici Helvetici, Volume 84, Issue 3, 2009.
[arXiv:0706.3904] [Journal] [MR2507250]
Amenable covers, volume and L²-Betti numbers of aspherical manifolds
accepted for J. Reine Angew. Math (Crelle's Journal).
[math.AT/0605627]
Homological invariants and quasi-isometry
appeared in Geom. Funct. Anal. (GAFA), Volume 16, Number 2 / April, 2006.
[math.AT/0312129] [Journal] [MR2231471]
L²-Betti numbers of discrete measured groupoids
appeared in Internat. J. Algebra Comput. 15 (2005), no. 5-6.
[math.AT/0312411] [Journal] [MR2197826]
Power series over the group ring of a free group and applications to Novikov-Shubin invariants
appeared in Proceedings of the School High-Dimensional Manifold Topology, Trieste, 2003.
[pdf] [MR2048733]

Expository papers:

Homotopy invariance of almost flat Betti numbers
joint with Thomas Schick
appeared in Enseign. Math. (2) 54 (2008), no. 1-2 (Guido's book of conjectures)
[pdf] [MR2454697]
Volume and L²-Betti numbers of aspherical manifolds
appeared in Proceedings of the Courant Colloquium Göttingen 2007 (ISBN 3-978-3-940344-56-4)
[Online edition] [pdf]

In preparation

Restricted measure equivalence rigidity of hyperbolic lattices.
joint with Uri Bader and Alex Furman.
See also these slides of a talk on this subject.
Sobolev homology of word-hyperbolic groups.
joint with Uri Bader and Alex Furman.
Homotopy colimits and Euler characteristics of categories.
joint with Tom Fiore and Wolfgang Lück.

Conferences and research seminars

Organizer of the summer school Geometry and Rigidity of Groups at the University of Münster, August 2009.
Other organizers: Arthur Bartels, Wolfgang Lück
Seminar on Analysis on metric spaces organized with Shmuel Weinberger at the University of Chicago, Winter 2008.
Here some notes of the talks. For more information see also Shmuel's seminar page.
- Notes by Thomas Zamojski of his talk on Rademacher's theorem.
- Extended notes of my series of talks on Bruce Kleiner's new proof of Gromov's polynomial growth theorem.
  See also this blog-entry by Terence Tao.
- My handwritten notes of Alex Eskin's talk on coarse differentiation.
- My handwritten notes of Kevin Whyte's two talks on Pierre Pansu's Rademacher theorem.
Organizer of the workshop L²-Invariants, Measure Theory and Geometric Group Theory at the University of Münster, March 2004 (Downlad the conference booklet).
Other organizers: Damien Gaboriau, Wolfgang Lück, Andrzej Zuk.

Invited presentations

Hausdorff Institute Bonn, Workshop: Rigidity in cohomology, K-theory, geometry and ergodic theory, November 2009
Universität Göttingen, Lecture series on "measurable group theory as a tool in geometry", August 2009
WWU Münster, Habilitationskolloquium, July 2009
University of Illinois at Chicago, Geometry, Topology, and Dynamics Seminar, March 2009
University of Regensburg Kolloquium, March 2009
University of Regensburg Kolloquium des Kepler-Forschungszentrums, November 2008
LMU München, Differentialtopologie-Seminar, November 2008
MFO Oberwolfach, Workshop on von Neumann algebras and ergodic theory of group actions, November 2008
University of Stuttgart, Colloquium, October 2008
MFO Oberwolfach, Topology workshop, September 2008
Banff International Research Station, Topics in von Neumann algebras, March 2008
[Slides] [Handout]
University of Michigan, Geometry seminar, February 12, 2008
Courant Research Center Göttingen, Courant-Colloquium "Göttingen trends in Mathematics", October 2007
[Slides] [Extended notes]
WWU Münster, Oberseminar Topologie, October 2007
Banff International Research Station, Topological and geometric rigidity, July 2007
[Slides]
Binghamton University,Topology seminar, April 2007
University of Urbana-Champaign, Seminar, April 2007
Banff International Research Station, Topology, February 2007
Ohio State University, Seminar, February 2007
University of Illinois at Chicago, Geometry, Topology, and Dynamics Seminar, November 2006
University of Karlsruhe, Conference on "Geometry and algebra of solvable groups", October 2006
MPI Bonn, Activity on Geometry and Group Theory, July 2006
MPI Bonn, Oberseminar Topologie, July 2006
CRM Montreal Conference on geometric group theory, July 2006
MFO Oberwolfach, Topological and Geometric Methods in Group Theory, April 2006
University of South Alabama, G3-conference, March 2006
University of Chicago, Topology/Geometry Seminar, March 2006
LMU München, Differentialtopologie-Seminar, January 2006
Nashville, Third Annual Spring Institute on Noncommutative Geometry and Operator Algebras, May 2005
University of Tel-Aviv, Seminar, May 2005
Hebrew University Jerusalem, Seminar, May 2005
Göttingen, GK-Kolloquium, January 2005
Luminy, Seminar, November 2004
University of Marseille, Seminar, November 2004
ENS Lyon, ENS-Seminar, November 2004
University of Grenoble, Tripod Seminaire, November 2004
MFO Oberwolfach, Topology workshop, September 2004
Bonn, NRW Topology meeting, April 2004
Diablerets, Invariants sous Quasi-Isometrie, April 2004
University of Augsburg, Differentialgeometrie-Seminar, November 2003
ETH Zürich, Seminar, June 2003
University of Basel, Colloquium, November 2001

last modified: January 20, 2009 by Roman Sauer