Seminars and Colloquia by Series

Wednesday, September 19, 2012 - 16:00 , Location: Skiles 06 , Lei Zhang , Georgia Tech , Organizer: Rafael de la Llave
Continuation of the exposition of N. Fenichel classical paper on the persistence of Normally Hyperbolic invariant manifolds.
Wednesday, September 12, 2012 - 16:00 , Location: Skiles 06 , Lei Zhang , Georgia Institute of technology , Organizer: Rafael de la Llave
We will present the classical work of N. Fenichel on persitence of overflowing manifolds.
Wednesday, September 5, 2012 - 16:00 , Location: Skiles 06 , Rafael de la Llave , Georgia Institute of technology , Organizer: Rafael de la Llave
We will present a classical proof of the center stable manifold.
Wednesday, August 22, 2012 - 15:00 , Location: Skiles 0t , T. Bartsch , Univ of Loughborough , Organizer: Rafael de la Llave
Thursday, May 3, 2012 - 16:00 , Location: Skiles 006 , Alan Diaz , Georgia Tech. , Organizer: Rafael de la Llave
In this introductory talk, we review the dynamical motivation for definingsymplectic manifolds, then describe a class of invariants called symplecticcapacities, which are closely related to both volume and the existence ofperiodic orbits. We explore the connections and differences between thesethree notions in the context of some basic phenomena/problems in symplecticgeometry: Gromov's nonsqueezing theorem, the difference between symplecticand volume-preserving diffeomorphisms, and the question of existence ofclosed characteristics on energy surfaces.
Wednesday, April 11, 2012 - 16:00 , Location: Skiles 005 , Mikel J. De Viana , Georgia Tech. , Organizer: Rafael de la Llave
In the 1990's Marina Ratner published a famous series of papers showing that ergodic measures invariant under unipotent flows over quotients $\Gamma/G$ are homogeneous. From this, she deduced many other remarkable properties for these flows (e.g that the closure of orbits are homogeneous and that orbits are uniformly distributed in their closures). To prove this result will require several lectures, but already the case of horocycle flow in $\Gamma/SL(2, \mathbb{R})$ presents several or her ideas. In this talk we will present the ideas of the proof in this case and present an application due to Margulis.

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