Seminars Sorted by Series

Geometry, Combinatorics and Algebraic Groups

Geometry/Dynamical Systems Seminar

Jan
26
2010

Geometry/Dynamical Systems Seminar

Rabinowitz-Floer Homology
Urs Frauenfelder
4:00pm|S-101

Rabinowitzi-Floer homology is the semi-infinite dimensional Morse homology associated to an action functional which played a major role in the pioneering work of Rabinowitz. Critical points of Rabinowitz action functional are Reeb orbits while...

Feb
23
2010

Geometry/Dynamical Systems Seminar

Lipschitz Maps From Spaces With Many Rectifiable Curves
4:00pm|S-101

We will survey results (partly joint with Kleiner, and with Kleiner and Naor) on possibly fractal metric spaces which in a suitable sense have many rectifiable curves. We will try to cover: differentiable structure, a bi-Lipschitz nonembedding...

Mar
02
2010

Geometry/Dynamical Systems Seminar

Floer Homology and Loop Space Topology I
4:00pm|S-101

Floer homology generated by periodic orbits of Hamiltonian systems is, in general, not a classical homology theory. However, on phase spaces of cotangent bundle type for systems equivalent to the geodesic flow, all known structures in loop space...

Mar
03
2010

Geometry/Dynamical Systems Seminar

Floer Homology and Loop Space Topology II
4:00pm|West Bldg. Lecture Hall

Floer homology generated by periodic orbits of Hamiltonian systems is, in general, not a classical homology theory. However, on phase spaces of cotangent bundle type for systems equivalent to the geodesic flow, all known structures in loop space...

Apr
13
2010

Geometry/Dynamical Systems Seminar

The Picard Lefschetz Theory of Complexified Morse Functions
Joseph Johns
4:00pm|S-101

We will explain how to construct a symplectic Lefschetz fibration with explicit regular fiber and vanishing spheres which models a complexified Morse function on a cotangent bundle. We will sketch at the end how this leads to a definition of...

Apr
20
2010

Geometry/Dynamical Systems Seminar

On the Multiplicity of Periodic Orbits for Tonelli Systems
Marco Mazzucchelli
4:30pm|S-101

In this talk I shall sketch a proof of the following result: on a closed configuration space M, the Euler-Lagrange system associated to any time-periodic Tonelli Lagrangian function L : R/Z x TM --> R admits infinitely many periodic solutions. More...

Oct
22
2010

Geometry/Dynamical Systems Seminar

Global Stringy Orbifold Cohomology, K-Theory and de Rham theory with Possible Applications to Landau-Ginzburg Theory
Ralph Kaufmann
4:00pm|S-101
Nov
19
2010

Geometry/Dynamical Systems Seminar

Implied Existence for 3-D Reeb Dynamics
Al Momin
4:00pm|S-101

Using a version of cylindrical contact homology on the complement of some Reeb orbits in a 3-dimensional contact manifold we will deduce that the existence of closed Reeb orbits with certain topological/dynamical properties implies the existence of...

Dec
03
2010

Geometry/Dynamical Systems Seminar

A Reidemeister-Singer Conjecture for Surface Diagrams
Jonathan Williams
4:00pm|S-101

There is a way to specify any smooth, closed oriented four-manifold using a surface decorated with simple closed curves, something I call a surface diagram. In this talk I will describe three moves on these objects, two of which are reminiscent of...

Dec
10
2010

Geometry/Dynamical Systems Seminar

Understanding Area Preserving Disk Maps Through Holomorphic Curves
4:00pm|S-101

Predicting the future for a Hamiltonian dynamical system is an old and notoriously difficult problem. I will present some evidence however that in the simplest situation where one iterates an area preserving map on the 2-disk, solutions to an...

Jan
19
2011

Geometry/Dynamical Systems Seminar

Contacting the Moon
Urs Frauenfelder
2:00pm|S-101

The restricted 3-body problem has an intriguing dynamics. A deep observation of Jacobi is that in rotating coordinates the problem admits an integral. In joint work with P. Albers, G. Paternain and O. van Koert, we proved that the corresponding...

Jan
19
2011

Geometry/Dynamical Systems Seminar

Weak Stability Boundary and Capture in the Three-Body Problem
Edward Belbruno
4:00pm|S-101

The problem of capture in the planar restricted three-body problem is addressed. In particular, weak capture is described, which occurs at a complicated region called the weak stability boundary, where the motion is chaotic in nature. It was first...

Jan
21
2011

Geometry/Dynamical Systems Seminar

The Cartan Geometry of the Rotating Kepler Problem
Otto van Koert
4:00pm|S-101

In this talk we shall discuss the Cartan geometry of the rotating Kepler problem. The rotating Kepler problem appears as the limit of the restricted planar three-body body when one of the masses goes to zero. As such, this problem plays the role of...

Jan
26
2011

Geometry/Dynamical Systems Seminar

Periodic Bounce Orbits of Prescribed Energy
2:00pm|S-101

Periodic bounce orbits are generalizations of billiard trajectories in the presence of a potential. Using an approximation technique by Benci-Giannoni we prove existence of periodic bounce orbits of prescribed energy. At the end of the talk I will...

Jan
26
2011

Geometry/Dynamical Systems Seminar

J-Curves in Degenerating Contact Manifolds
4:00pm|S-101

We will discuss some recent SFT-type compactness results for J-curves (i.e. pseudo-holomorphic curves) in the symplectization of a contact manifold which is stretched along a special hypersurface. This procedure is called "sideways stretching" and...

Apr
08
2011

Geometry/Dynamical Systems Seminar

The Dehn Function of SL(n;Z)
4:00pm|S-101

The Dehn function is a group invariant which connects geometric and combinatorial group theory; it measures both the difficulty of the word problem and the area necessary to fill a closed curve in an associated space with a disc. The behavior of the...

Glimpses of Mathematics, Now and Then: A Celebration of Karen Uhlenbeck's 80th birthday

Sep
17
2022

Glimpses of Mathematics, Now and Then: A Celebration of Karen Uhlenbeck's 80th birthday

Higgs bundles and Higher Teichmüller spaces
Brian Collier
10:15am|Simonyi 101 and Remote Access

Abstract: The Teichm\"uller space of a compact surface S is realized as a connected component of the space of conjugacy classes of representations of the fundamental group into the Lie group PSL(2,R). This component is distinguished by the fact that...

Sep
18
2022

Glimpses of Mathematics, Now and Then: A Celebration of Karen Uhlenbeck's 80th birthday

Geometry, fluids and the Laplacian
Magdalena Czubak
10:15am|Simonyi 101 and Remote Access

Abstract:  We are interested in a fluid flow on a general Riemannian manifold.  There are inequivalent formulations of the governing equations.  One reason for this comes from having several Laplacians to choose from when working with vector fields...

Goncharov Reading Group

Feb
05
2014

Goncharov Reading Group

11:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Feb
12
2014

Goncharov Reading Group

An introduction to Hodge theory
Christopher Brav
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Feb
19
2014

Goncharov Reading Group

More on Hodge theory
Christopher Brav
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Feb
26
2014

Goncharov Reading Group

An introduction to algebraic K-theory
Daniel Grayson
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Mar
05
2014

Goncharov Reading Group

Hyperbolic manifolds
Tudor Dimofte
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Mar
19
2014

Goncharov Reading Group

Introduction to motives
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Mar
26
2014

Goncharov Reading Group

Dilogarithms
Tudor Dimofte and Christopher Brav
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Apr
02
2014

Goncharov Reading Group

Back to the paper!
Inna Zakharevich and Christopher Brav
10:00am|West Bldg. Lect. Hall

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Apr
09
2014

Goncharov Reading Group

More on motives
Chuck Weibel
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Apr
23
2014

Goncharov Reading Group

To Be Announced
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Apr
30
2014

Goncharov Reading Group

To Be Announced
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

May
07
2014

Goncharov Reading Group

To Be Announced
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

May
14
2014

Goncharov Reading Group

To Be Announced
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

May
21
2014

Goncharov Reading Group

To Be Announced
10:00am|S-114

The Goncharov reading group is an informal seminar which will read the paper "Volumes of hyperbolic manifolds and mixed Tate motives" and related materials. We will meet on Wednesdays at 10 am in Simonyi 114.

Group Theory/Dynamics Talk

Dec
09
2022

Group Theory/Dynamics Talk

How Small Can a Group or a Graph be to Admit a Non-Trivial Poisson Boundary?
1:30pm|Simonyi Hall 101 and Remote Access

We review results about random walks on groups, discussing results and conjectures relating critical constant for recurrence/transience, growth and Poisson boundary.

Much less is known about behavior of random walks on Schreier graphs. Since any...