2009:

• Witten deformation of non-selfadjoint Laplacians. Special meeting of the Central European Seminar on Differential Geometry in Honor of the 60th Birthday of Peter Michor, Mikulov, Czech Republic, May 29-30, 2009.

• Non-selfadjoint Laplacians and analytic torsion. Global Analysis seminar, University of Bonn, July 1st, 2008.

• Exponential growth and Novikov complex. Topology seminar, Ohio State University, Columbus, OH, September 25, 2007.
• Complex valued Ray--Singer torsion. Algebraic Topology: Old and New, M.M. Postnikov Memorial Conference, Banach Center, Bedlewo, June 23rd, 2007.   Transparencies of the talk: DVI -- PS -- PDF

• Complex valued Ray-Singer torsion. Topology seminar, Ohio State University, Columbus, OH, September 26, 2006.
• Complex Ray-Singer torsion. Conference C*-algebras and elliptic theory. II, Banach Center, Bedlewo, January 27th, 2006.   Abstract: DVI -- PS -- PDF   Transparencies of the talk: DVI -- PS -- PDF

• Morse-Novikov vector fields and exponential growth. Topology Seminar, Max Planck Institut for Mathematics, Bonn, March 21st, 2005.

• Exponential growth and Novikov conjecture. Conference Topology of closed one-forms, ETH Zürich, December 15th, 2004.   Transparencies of the talk: DVI -- PS -- PDF
• The geometric complex of a Morse--Bott--Smale vector field and an extension of a theorem of Bismut--Zhang. AMS Meeting, Evanston, October 23rd, 2004.   Abstract: DVI -- PS -- PDF   Transparencies of the talk: DVI -- PS -- PDF
• An extension of a theorem by Bismut--Zhang to Morse--Bott vector fields. Topology Seminar, Max Planck Institut for Mathematics, Bonn, September 17th, 2004.   Transparencies of the talk: DVI -- PS -- PDF
• Smooth perfectness of diffeomorphism groups. Conference Geometry and Analysis on Manifolds, Celebrating the 60th birthday of Dan Burghelea, Ohio State University, Columbus, OH, March 26--28th, 2004.   Transparencies of the talk: DVI -- PS -- PDF

• Poisson harmonic forms. Topology seminar, Ohio State University, Columbus, OH, September 3, 2003.
• Harmonic cohomology of symplectic manifolds. 5th Conference Geometry and Topology of Manifolds, Krynica, Poland, April 27--May 3, 2003.   Transparencies of the talk: DVI -- PS -- PDF
• Harmonic cohomology of symplectic manifolds. The 23rd Winter School Geometry and Physics, Srni, Czech Republic, January 18--25, 2003.

• Symplectic manifolds and harmonic classes. Seminar of Geometry and Topology, West University of Timisoara, Timisoara, Romania, July 10, 2002.   Transparencies of the talk: DVI -- PS -- PDF
• Harmonic cohomology of symplectic manifolds. The 22nd Winter School Geometry and Physics, Srni, Czech Republic, January 12-19, 2002.   Transparencies of the talk: DVI -- PS -- PDF
• Harmonic cohomology of symplectic manifolds. Analysis seminar, University Zurich, Zurich, Swizerland, January 10, 2002.   Transparencies of the talk: DVI -- PS -- PDF

• Floer cohomology based on non-contractible 1-periodic trajectories. 8th International Conference on Differential Geometry and its Applications, Opava, Czech Republic, August 27-31, 2001.   Transparencies of the talk: DVI -- PS -- PDF
• Floer cohomology and non-contractible periodic orbits of time dependent symplectic vector fields. Geometric Analysis seminar, Ohio State University, Columbus, OH, January 19, 2001.
• Totally geodesic subgroups of diffeomorphism groups. Topology seminar, Ohio State University, Columbus, OH, January 16, 2001.

• A survey on locally conformal symplectic manifolds. Howard Conference on Infinite Dimensional Lie Groups in Geometry and Representation Theory, Howard University, Washington, DC, August 17-21, 2000.   Preprint of my contribution to the proceedings: DVI -- PS -- PDF
• Locally conformal symplectic manifolds. Topology seminar, Ohio State University, Columbus, OH, April 25, 2000.
• On the group of diffeomorphisms preserving a locally conformal symplectic structure. The 20th Winter School Geometry and Physics, Srni, Czech Republic, January 15-22, 2000.

• Fragmentation and deformation for modular groups of diffeomorphisms. The 18th Winter School Geometry and Physics, Srni, Czech Republic, January 10-17, 1998.

• Second Calabi invariant for the group of Poisson diffeomorphisms. Workshop on Lie groups and Lie algebras in infinite dimension, Stefan Banach International Mathematical Center, Warsaw, Poland, September 8-13, 1997.