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Autumn Semester 2014

Date / Time Speaker Title Location
1 October 2014
15:45-16:45
Domingo Toledo
University of Utah, Salt Lake City
Event Details

Geometry Seminar

Title Self-interesections of closed complex geodesics in complex hyperbolic surfaces
Speaker, Affiliation Domingo Toledo, University of Utah, Salt Lake City
Date, Time 1 October 2014, 15:45-16:45
Location HG G 43
Abstract A complex hyperbolic surface is a compact, smooth complex surface covered by the unit ball. A closed complex geodesic is a compact (immersed) complex curve that is totally geodesic in the invariant metric. Complex hyperbolic surfaces with arithmetic fundamental group are divided into two classes: those that have no closed complex geodesics, and those that have infinitely many. In the latter case, only finitely many complex geodesics are embedded, in fact the number of self-intesections must grow with the area. A proof of this fact will be presented, as a consequence of an equidistribution for theorem for complex geodesics derived from Ratner’s theorem. This is joint work with Martin Möller.
Self-interesections of closed complex geodesics in complex hyperbolic surfacesread_more
HG G 43
15 October 2014
15:45-16:45
David Hume
UC Louvain
Event Details

Geometry Seminar

Title Acylindrical hyperbolicity for groups acting on buildings
Speaker, Affiliation David Hume, UC Louvain
Date, Time 15 October 2014, 15:45-16:45
Location HG G 43
Abstract We give a sufficient condition to detect acylindrical hyperbolicity of a group from a specified action on a non-spherical building and use it to deduce the above property for arbitrary graph products and orthogonal forms of Kac-Moody groups. This is joint work with Pierre-Emmanuel Caprace.
Acylindrical hyperbolicity for groups acting on buildingsread_more
HG G 43
22 October 2014
15:45-16:45
Oskar Hamlet
Chalmers University of Technology (Sweden)
Event Details

Geometry Seminar

Title Tight maps and homomorphisms
Speaker, Affiliation Oskar Hamlet, Chalmers University of Technology (Sweden)
Date, Time 22 October 2014, 15:45-16:45
Location HG G 43
Abstract Tight homomorphisms/maps were introduced as a tool for studying certain aspects of representations with maximal Toledo invariant. In this talk I will give a brief introduction to these maps and present an overview of my work classifying them.
Tight maps and homomorphismsread_more
HG G 43
29 October 2014
15:45-16:45
Andrea Schioppa
ETH Zürich
Event Details

Geometry Seminar

Title Vector fields on metric mesure spaces, and 1-rectifiable structure
Speaker, Affiliation Andrea Schioppa, ETH Zürich
Date, Time 29 October 2014, 15:45-16:45
Location HG G 43
Abstract In this talk I will describe a general approach to differentiaton of real-valued Lipschitz functions defined on metric measure spaces. As an application, I will discuss a quantitative characterization of differentiability spaces in the sense of Cheeger and Keith.
Vector fields on metric mesure spaces, and 1-rectifiable structureread_more
HG G 43
5 November 2014
15:45-16:45
Thomas Mettler
ETH Zurich
Event Details

Geometry Seminar

Title Projective surfaces, holomorphic curves and the SL(3,R)-Hitchin component
Speaker, Affiliation Thomas Mettler, ETH Zurich
Date, Time 5 November 2014, 15:45-16:45
Location HG G 43
Abstract A projective structure P on a surface M is an equivalence class of affine torsion-free connections on M where two connections are called projectively equivalent if they share the same geodesics up to parametrisation. An oriented projective surface (M,P) defines a complex surface Z together with a projection to M whose fibres are holomorphically embedded disks. Moreover, a conformal connection in the projective equivalence class corresponds to a section whose image is a holomorphic curve in Z. Findig a section of Z->M whose image is "as close as possible" to a holomorphic curve turns out to be related to the parametrisation of the SL(3,R)-Hitchin component in terms of holomorphic cubic differentials.
Projective surfaces, holomorphic curves and the SL(3,R)-Hitchin componentread_more
HG G 43
12 November 2014
15:45-16:45
Andrea Mondino
ETH Zürich
Event Details

Geometry Seminar

Title Some analytic and geometric properties of non smooth spaces with lower Ricci curvature bounds
Speaker, Affiliation Andrea Mondino, ETH Zürich
Date, Time 12 November 2014, 15:45-16:45
Location HG G 43
Abstract In the talk I will introduce and discuss geometric/analytic properties of non smooth spaces with Ricci curvature lower bounds. Such class contains the Gromov-Hausdorff limits of Riemannian manifolds satisfying Ricci curvature lower bounds and it is a very active field in contemporary research.
Some analytic and geometric properties of non smooth spaces with lower Ricci curvature boundsread_more
HG G 43
26 November 2014
15:45-16:45
Pierre-Emmanuel Caprace
Université catholique de Louvain
Event Details

Geometry Seminar

Title Sharply multiply transitive locally compact groups
Speaker, Affiliation Pierre-Emmanuel Caprace, Université catholique de Louvain
Date, Time 26 November 2014, 15:45-16:45
Location HG G 43
Abstract A permutation group is called sharply n-transitive if it acts freely and transitively on the set of ordered n-tuples of distinct points. The investigation of such permutation groups is a classical branch of group theory; it led Emile Mathieu to the discovery of the smallest finite simple sporadic groups in the 1860's. In this talk I will discuss the case where the permutation group is assumed to be a locally compact transformation group, and explain how this set-up is related to Gromov hyperbolicity and to arithmetic lattices in products of trees.
Sharply multiply transitive locally compact groupsread_more
HG G 43
3 December 2014
15:45-16:45
Binoy Raveendran
Université de Neuchâtel
Event Details

Geometry Seminar

Title On geodesic conjugacies
Speaker, Affiliation Binoy Raveendran, Université de Neuchâtel
Date, Time 3 December 2014, 15:45-16:45
Location HG G 43
Abstract The question of whether a time-preserving geodesic conjugacy determines a closed, negatively curved Riemannian manifold up to an isometry is one of the central problems in Riemannian geometry. While an answer to the question in this generality has yet remained elusive, we discuss some available affirmative results.
On geodesic conjugaciesread_more
HG G 43

Organizers: Marc Burger, Manfred Einsiedler, Alessandra Iozzi, Urs Lang, Viktor Schröder

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