Roman Sauer
I moved to the Karlsruhe Institute of Technology. Here is my new webpage.
Upcoming events
Lehre
WS 2012/13: (KIT Karlsruhe)
 Vorlesung: Liegruppen und Liealgebren
 Seminar zur systolischen Geometrie
 Proseminar: Eulers Trickkiste (Programm)
 Seminar der AG Topologie
SS 2012:
 Vorlesung: Topologie II (Mi 8:3010:00 in M104 und Fr 10:1512:00 in M 104)
 Bachelorseminar (Fr 12:3014:00 in M 102)
 Seminar: Gebäude (Do 1214 in M 104)
 Oberseminar: Globale Analysis und Geometrie (Mi 1012 in M103)
WS 2011/12:
 Vorlesung: Topologie I (Mi 810 in M104 und Fr 1012 in M 104)
 Seminar: Liegruppen und ihre Darstellungen (Do 1416 in M 102)
 Seminar: Differentialtopologie (Di 1214 in M 101)
 Oberseminar: Stable cohomology of arithmetic groups after Borel (Fr 810 in M006) (Programm)
 Oberseminar: Globale Analysis und Geometrie (Mi 1012 in M103)
Publications
Research papers:

Weak notions of normality and vanishing up to rank in L²cohomology
joint with Uri Bader and
Alex Furman
[arXiv:1206.4793]

On the growth of Betti numbers in padic analytic towers
joint with Nicolas Bergeron and Peter Linnell and
Wolfgang Lück
[arXiv:1204.3298]

Integrable measure equivalence and rigidity of hyperbolic lattices
joint with Uri Bader and
Alex Furman
to appear in Inventiones
[arXiv:1006.5193]

Efficient subdivision in hyperbolic groups and applications
joint with Uri Bader and
Alex Furman
to appear in Groups, Geometry, and Dynamics
[arXiv:1003.1562]

Euler characteristics of categories and homotopy colimits
joint with Tom Fiore and
Wolfgang Lück
Documenta Math. 16 (2011), 301354
[arXiv:1007.3868] [Journal] [MR2804514]

Spectral distribution and L²isoperimetric profile of Laplace operators on groups
joint with Alexander Bendikov and
Christophe Pittet
Mathematische Annalen 354 (2012), 4372
[arXiv:0901.0271] [Journal] [MR2957618 ]

Finiteness obstructions and Euler characteristics of categories
joint with Tom Fiore and
Wolfgang Lück
Advances in Mathematics, Volume 226, Issue 3, 2011, 2371–2469
[arXiv:0908.3417] [Journal] [MR2739781]

The limit of F_pBetti numbers of a tower of finite covers with amenable fundamental groups
joint with Peter Linnell and
Wolfgang Lück
Proc. Amer. Math. Soc. 139 (2011), 421434
[arXiv:1003.0434] [Journal] [MR2736326]

L²torsion, the measuretheoretic determinant conjecture, and uniform measure equivalence
joint with and Wolfgang Lück and Christian Wegner
Journal of Topology and Analysis, Volume 2, Issue 2, 2010, 145171
[arXiv:0903.2925] [Journal] [MR2652905]

A spectral sequence to compute L²Betti numbers of groups and groupoids
joint with Andreas Thom
Journal of the London Mathematical Society, Volume 81, Number 3, 2010, 747773
[arXiv:0707.0906] [Journal] [MR2650795
]

Degree theorems and Lipschitz simplicial volume for
nonpositively curved manifolds of finite volume
joint with Clara Löh
Journal of Topology, Volume 2, Number 1, 2009, 193225
[arXiv:0710.1635]
[Journal] [MR2499443]

Simplicial Volume of Hilbert modular varieties
joint with Clara Löh
Commentarii Mathematici Helvetici, Volume 84, Issue 3, 2009, 457470
[arXiv:0706.3904] [Journal] [MR2507250]

Amenable covers, volume and L²Betti numbers of
aspherical manifolds
J. Reine Angew. Math (Crelle's Journal), Issue 636, November 2009, 4792
[math.AT/0605627] [Journal] [MR2572246 ]

Homological invariants and quasiisometry
Geom. Funct. Anal. (GAFA), Volume 16, Number 2,
2006, 476–515
[math.AT/0312129]
[Journal]
[MR2231471]

L²Betti numbers of discrete measured groupoids
Internat. J. Algebra Comput. 15
(2005), no. 56, 1169–1188
[math.AT/0312411]
[Journal]
[MR2197826]

Power series over the group ring of a free group and applications to NovikovShubin invariants
Proceedings of the School HighDimensional
Manifold Topology, Trieste, 2003.
[pdf]
[MR2048733]
Expository and miscellaneous papers:

The asymptotic growth of twisted torsion
joint with Nicolas Bergeron and
Wolfgang Lück
[pdf]

Homotopy invariance of almost flat Betti numbers
joint with Thomas
Schick
Enseign. Math. (2) 54 (2008), no. 12 (Guido's book of conjectures)
[pdf] [MR2454697]

Volume and L²Betti numbers of aspherical manifolds
Proceedings of the Courant Colloquium
Göttingen 2007 (ISBN 39783940344564)
[Online edition] [pdf] [MR2906042]
Organized conferences and schools
Invited presentations
 Topology and Groups, Berlin, June 2012
 MittagLeffler institute, Stockholm, Geometric and Analytic Aspects of Group Theory, April 2012
 Beit Hatfutsot, Tel Aviv, Transcending Tradition  Jewish Mathematicians in GermanSpeaking Academic Culture, November 2011
 Technion, Haifa, Conference on geometric group theory, June 2011
 University of Bonn, 14th NRW Topology meeting, November 2011
 Technion, Haifa, Colloquium, June 2010
[Slides]
 Technion, Haifa, Geometry Seminar, June 2010
 ETH Zürich, Algebra and Topology Seminar, March 2010
 ETH Zürich, Geometry Seminar, March 2010
 University of Copenhagen, Workshop: Von Neumann algebras and group actions, February 2010
 University of Regensburg, Kolloquium,
December 2009
[Slides]
 Hausdorff Institute Bonn, Workshop: Rigidity in cohomology, Ktheory, geometry and ergodic theory, November 2009
 University of Osnabrück, Kolloquium, October 2009
 University of Göttingen, Lecture series on "measurable group theory as a tool in geometry", August 2009
[Notes by Anke Pohl]
 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 KeplerForschungszentrums,
November 2008
 LMU München, DifferentialtopologieSeminar,
November 2008
 MFO Oberwolfach,
Workshop on von Neumann algebras and ergodic theory of group actions,
November 2008
 University of Stuttgart, Kolloquium,
October 2008
[Slides]
 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, CourantColloquium "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
UrbanaChampaign, 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,
G3conference, March 2006
 University of
Chicago, Topology/Geometry Seminar, March 2006
 LMU München, DifferentialtopologieSeminar,
January 2006
 Nashville, Third Annual Spring Institute on Noncommutative
Geometry and Operator Algebras, May 2005
 University of TelAviv, Seminar, May 2005
 Hebrew University Jerusalem, Seminar, May 2005
 University of Göttingen, GKKolloquium, January 2005
 Luminy, Seminar, November 2004
 University of Marseille, Seminar, November 2004
 ENS Lyon, ENSSeminar, November 2004
 University of Grenoble, Tripod Seminaire, November
2004
 MFO Oberwolfach, Topology workshop, September
2004
 Bonn, NRW Topology meeting, April 2004
 Diablerets, Invariants sous QuasiIsometrie, April 2004
 University of Augsburg, DifferentialgeometrieSeminar,
November 2003
 ETH Zürich, Seminar, June 2003
 University of Basel, Seminar, November 2001
last modified: June 22, 2012 by
Roman Sauer