Oberseminar Geometrie, Topologie und Analysis

H. Geiges, G. Marinescu, U. Semmelmann, G. Thorbergsson

Sommersemester 2009

Freitag, 10:30-11:30, Seminarraum 1

15.5.09 Dr. William Kirwin (MPI Leipzig)
Lagrangian fibrations of coadjoint orbits from the Iwasawa decomposition

22.5.09 Prof. Krishnan Shankar (University of Oklahoma, z.Zt. Münster)
Riemannian submersions from compact Lie groups

Abstract: We construct infinitely many examples of Riemannian submersions GM, where G is a simple, compact Lie group, M is a smooth Riemannian manifold and such that M is not a quotient of G by any group U ⊆ Diff(G) acting freely on G. This is joint work with Martin Kerin.
29.5.09 Prof. Viktor Schroeder (Universität Zürich)
Ptolemy spaces

Abstract: A metric space (X,d) is called a Ptolemy space if for any quadrupels of points x,y,z,w in X the three numbers d(x,y)d(z,w), d(x,z)d(y,w) and d(x,w)d(y,z) satisfy the triangle inequality. Ptolemy spaces arise naturally if one studies the ideal boundary of a noncompact simply connected manifold of negative curvature or more generally CAT(-1) spaces. We give an introduction to the geometry of these spaces with applications to manifolds of negative curvature.
12.6.09 Dr. Chin-Yu Hsiao (Göteborg)
On the singularities of the Bergman kernel

Abstract: In this work, we obtain the full asymptotic expansion of the Bergman projection for (0,q)-forms when the Levi form is non-degenerate. This generalizes a result of Boutet de Monvel and Sjöstrand for (0,0)-forms. We will explain our method in an elementary fashion. We hope that this talk can serve as an introduction to certain microlocal techniques with applications in complex analysis.
Prof. András Stipsicz (Budapest)
Heegaard Floer invariants in contact topology

Abstract:This is the second lecture in a loosely connected series of three lectures. See this separate announcement.
Prof. András Stipsicz (Budapest)
Surface singularities with rational homology disk smoothings

10.7.09 Prof. Wolfgang Ziller (University of Pennsylvania)
Positive Schnittkrümmung: Beispiele und Hindernisse in Faserbündeln

H. Geiges, 5.4.02