Seminars and Colloquia by Series

How to Partition a Mixed Phase Space - with Applications to Atomic Physics

Series
Other Talks
Time
Monday, March 1, 2010 - 15:00 for 1 hour (actually 50 minutes)
Location
Howey N110
Speaker
Kevin Mitchell – University of California, Merced
Hamiltonian systems typically exhibit a mixture of chaos and regularity, complicating any scheme to partition phase space and extract a symbolic description of the dynamics. In particular, the dynamics in the vicinity of stable islands can exhibit extremely complicated topology. We present an approach to extracting symbolic dynamics in such systems using networks of nested heteroclinic tangles-- fundamental geometric objects that organize phase space transport. These tangles can be used to progressively approximate the behavior in the vicinity of stable island chains. The net result is a symbolic approximation to the dynamics, and an associated phase-space partition, that includes the influence of stable islands. The utility of this approach is illustrated by examining two applications in atomic physics -- the chaotic escape of ultracold atoms from an atomic trap and the chaotic ionization of atoms in external fields.

Club Math - Mathematics of the Lottery

Series
Other Talks
Time
Wednesday, February 24, 2010 - 16:30 for 1 hour (actually 50 minutes)
Location
Skiles 269
Speaker
Skip Garibaldi – Department of Mathematics and Computer Science
Dr. Skip Garibaldi, Emory University's Winship Distinguished Professor, will make a presentation on Mathematics of the Lottery. He will discuss his expository article: "Finding good bets in the lottery, and why you shouldn't take them" recently published in the American Mathematical Monthly, Volume 117 (2010) 3-26.

Georgia Scientific Computing Symposium

Series
Other Talks
Time
Saturday, February 20, 2010 - 09:00 for 8 hours (full day)
Location
Skiles 249
Speaker
Georgia Scientific Computing Symposium – School of Mathematics, Georgia Tech
The purpose of the Georgia Scientific Computing Symposium (GSC 2010) is to provide an opportunity for professors, postdocs and graduate students in the Atlanta area to meet in an informal setting, to exchange ideas, and to highlight local scientific computing research. The one-day symposium is open to the whole research community. The event is free but registration is required.

ARC Colloquium - Saving Space by Algebraization

Series
Other Talks
Time
Wednesday, February 10, 2010 - 10:03 for 1 hour (actually 50 minutes)
Location
Klaus 1116W
Speaker
Daniel Lokshtanov – Institutt for Informatikk, Universitetet i Bergen
The Subset Sum and Knapsack problems are fundamental NP-complete problems and the pseudo-polynomial time dynamic programming algorithms for them appear in every algorithms textbook. The algorithms require pseudo-polynomial time and space. Since we do not expect polynomial time algorithms for Subset Sum and Knapsack to exist, a very natural question is whether they can be solved in pseudo-polynomial time and polynomial space. In this paper we answer this question affrmatively, and give the first pseudo-polynomial time, polynomial space algorithms for these problems. Our approach is based on algebraic methods and turns out to be useful for several other problems as well. If there is time i will also show how our method can be applied to give polynomial space exact algorithms for the classical Traveling Salesman, Weighted Set Cover and Weighted Steiner Tree problems. Joint work with Jesper Nederlof.

Message Passing Networks

Series
Other Talks
Time
Friday, February 5, 2010 - 15:00 for 1 hour (actually 50 minutes)
Location
Klaus 1116E
Speaker
Jinwoo Shin – Massachusetts Institute of Technology

Please Note: Refreshments in Room 2222, Klaus Building from 2-3 PM.

Simple, distributed and iterative algorithms, popularly known as the message passing algorithms, have emerged as the architecture of choice for engineered networks as well as cannonical behavioral model for societal and biological networks. Despite their simplicity, message passing algorithms have been surprisingly effective. In this talk, I will try to argue in favor of such algorithms by means of two results in the context of designing efficient medium access in wireless networks and modeling agent behavior in road transportation networks. See the full abstract,

Southeast Geometry Seminar

Series
Other Talks
Time
Monday, December 7, 2009 - 08:00 for 8 hours (full day)
Location
University of Alabama, Birmingham
Speaker
Southeast Geometry Seminar – University of Alabama, Birmingham

The Southeast Geometry Seminar is a series of semiannual one-day events focusing on geometric analysis. These events are hosted in rotation by the following institutions:

  • The University of Alabama at Birmingham
  • The Georgia Institute of Technology
  • Emory University
  • The University of Tennessee Knoxville

The following five speakers will give presentations on topics that include geometric analysis, and related fields, such as partial differential equations, general relativity, and geometric topology.

  • Natasa Sesum (U Penn)
  • Alexandru Ionescu (U Wisconsin)
  • Sergiu Klainerman (Princeton U)
  • Alex Freire (U Tennessee Knoxville)
  • Christian Hainzl (UAB)

A poster session will be hosted. There will also be an evening public lecture by plenary speaker Sergiu Klainerman entitled The Mathematical Magic of Black Holes.

Undergraduate Research Seminar

Series
Other Talks
Time
Friday, December 4, 2009 - 15:00 for 1.5 hours (actually 80 minutes)
Location
Skiles 168
Speaker
Michelle Delcourt and Leo Chen – School of Mathematics, Georgia Tech

Leo Chen: The Shape and Stability of a Flexible Sheet in a von Karman Vortex Street

Michelle Delcourt: Dessin and Manturov bracket shuffles
In this talk we will explore the connections between knot theory and combinatorics. Links are related to Grothendieck's dessins d'enfants. Cartographic one-vertex dessins can be represented by chord diagrams. The diagrams can be recorded as "words" using a finite alphabet (k-bracket parenthesis system). Many combinatorial objects are related to these Manturov bracket structures.

Cohomology and the Riemann-Roch theorem

Series
Other Talks
Time
Wednesday, December 2, 2009 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 255
Speaker
Kangkang Wang – School of Mathematics, Georgia Tech
We will present a sheaf-theoretic proof of the Riemann-Roch theorem for projective nonsingular curves.

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