All Seminars
| Title: Exact Minimum Degree Thresholds for Perfect Matchings in Uniform Hypergraphs |
|---|
| Seminar: Combinatorics |
| Speaker: Yi Zhao of Georgia State University |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2012-10-26 at 4:00PM |
| Venue: MSC W303 |
| Download Flyer |
| Abstract: Given positive integers $k$ and $d$ where $k/2 \leq d \leq k-1$, we give a minimum $d$-degree condition that ensures a perfect matching in a $k$-uniform hypergraph. This condition is best possible and extends the work of Pikhurko, Rödl, Ruci\'{n}ski and Szemerédi. Our approach makes use of the absorbing method. This is a joint work with Andrew Treglown. |
| Title: Ranks of elliptic curves |
|---|
| Seminar: Algebra and Number Theory |
| Speaker: Karl Rubin of UC Irvine |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-25 at 4:00PM |
| Venue: MSC W201 |
| Download Flyer |
| Abstract: I will discuss some recent conjectures and results on the distribution of Mordell-Weil ranks and Selmer ranks of elliptic curves. After some general background, I will specialize to families of quadratic twists, and describe some recent results in detail. |
| Title: An approach to nonsolvable base change for GL(2) |
|---|
| Seminar: Algebra and Number Theory |
| Speaker: Jayce Getz of Duke University |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-25 at 5:15PM |
| Venue: MSC W201 |
| Download Flyer |
| Abstract: Motivated by Langlands' beyond endoscopy idea, the speaker will present a conjectural trace identity that is essentially equivalent to base change and descent of automorphic representations of GL(2) along a nonsolvable extension of fields. |
| Title: The arithmetic of special values |
|---|
| Seminar: Algebra and Number Theory |
| Speaker: Cristian Popescu of UCSD |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-24 at 3:00PM |
| Venue: W306 |
| Download Flyer |
| Abstract: I will discuss some of my recent joint work with Greither on several classical conjectures on special values of equivariant Artin L-functions. |
| Title: Finding a role for structural graph theory in real-world network analysis |
|---|
| Seminar: The SIAM Student Chapter |
| Speaker: Blair Sullivan of Oak Ridge National Laboratory |
| Contact: Alexis Aposporidis, aapospo@emory.edu |
| Date: 2012-10-23 at 4:00PM |
| Venue: W306 |
| Download Flyer |
| Abstract: Network science is a rapidly growing interdisciplinary field with methods and applications drawn from across the natural, social, and information sciences. Perhaps surprisingly, very few approaches use techniques from the rich literature of structural graph theory. In this talk, we discuss some first steps towards integrating what have been predominantly theoretical results into tools for scalable network analysis.\\ \\ Tree-like structures arise extensively in network science - for example, hierarchical structures in biology, hyperbolic routing in the internet, and core-periphery behavior in social networks. As such, this talk focuses on ways to use tree decompositions, key combinatorial objects used in graph minor theory, in Tandem with k-cores and Gromov hyperbolicity to provide structural characterization of and improve inference on complex networks. We also discuss new algorithms using tree decompositions to enable scalable solution of certain graph optimization problems in a high performance computing environment. |
| Title: Resonances on hyperbolic surfaces |
|---|
| Seminar: Analysis and Differential Geometry |
| Speaker: Professor David Borthwick of Emory University |
| Contact: Vladimir Oliker, oliker@mathcs.emory.edu |
| Date: 2012-10-23 at 4:00PM |
| Venue: MSC W301 |
| Download Flyer |
| Abstract: The spectral theory of compact hyperbolic surfaces is a classical topic with many interesting results, most of which originate in Atle Selberg's approach to the study of automorphic forms. At first glance, Selberg's techniques do not appear to extend to non-compact surfaces of infinite area. However, in the last 15 years, thanks to breakthroughs in geometric scattering theory and the theory of resonances, we have developed a much more complete picture of the spectral theory in the infinite-area case. Many results of the Selberg theory turn out to have surprisingly close analogs in this setting, despite the radically different character of the spectral theory.\\ \\ In this talk we will try to give an accessible introduction to the spectral theory of hyperbolic surfaces, with our main goal being to introduce recent developments in the infinite-area setting. |
| Title: Tropical complexes |
|---|
| Seminar: Algebra |
| Speaker: Dustin Cartwright of Yale University |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-23 at 5:00PM |
| Venue: W306 |
| Download Flyer |
| Abstract: A tropical complex is a simplicial complex together with some additional numerical, which come from a semistable degeneration of a variety. Tropical complexes generalize to higher dimensions some of the analogies between curves and graphs which has been studied in tropical geometry. I will introduce tropical complex and talk about some of the connections to classical algebraic geometry. |
| Title: Combinatorics of splice graphs |
|---|
| Colloquium: N/A |
| Speaker: Dustin Cartwright of Yale University |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-22 at 4:00PM |
| Venue: W302 |
| Download Flyer |
| Abstract: A splice graph is a way of modeling the alternative splicings of a gene, which are different ways of forming related proteins from the same genetic building blocks. The characterization of this alternative splicing is a major area of study in contemporary biology. I will talk about some of the combinatorics relevant to splice graphs. Also, I will talk about some of the implications for inferring splice graphs from data. |
| Title: Upper bounds for Euclidean minima of abelian fields |
|---|
| Seminar: Algebra |
| Speaker: Eva Bayer of EPFL |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-17 at 3:00PM |
| Venue: W306 |
| Download Flyer |
| Abstract: The Euclidean division is a basic tool when dealing with the ordinary integers. It does not extend to rings of integers of algebraic number fields in general. It is natural to ask how to measure the 'deviation' from the Euclidean property, and this leads to the notion of Euclidean minimum. The case of totally real number fields is of especial interest, in particular because of a conjectured upper bound (conjecture attributed to Minkowski). The talk will present some recent results, obtained jointly with Piotr Maciak. |
| Title: Quantum Modular Forms |
|---|
| Seminar: Number Theory |
| Speaker: Ken Ono of Emory University |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-10-17 at 4:00PM |
| Venue: W306 |
| Download Flyer |
| Abstract: |