All Seminars
| Title: 3-dimensional hyperbolic manifolds as discretized configuration spaces of simple graphs |
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| Defense: Honors Thesis |
| Speaker: Michelle Chu of Emory University |
| Contact: Aaron Abrams, |
| Date: 2011-04-13 at 2:00PM |
| Venue: MSC E406 |
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| Abstract: |
| Title: Characteristic Properties of Mobius Transformations and Quasiconformal Mappings |
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| Defense: Honors Thesis |
| Speaker: Daniel Orner of Emory University |
| Contact: Shanshuang Yang, syang@mathcs.emory.edu |
| Date: 2011-04-13 at 3:00PM |
| Venue: MSC E406 |
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| Abstract: |
| Title: Weierstrass points on the Drinfeld modular Curve $X_0(\mathfrak{p})$ |
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| Seminar: Algebra and Number Theory |
| Speaker: Christelle Vincent of University of Wisconsin at Madison |
| Contact: Zachary A Kent, kent@mathcs.emory.edu |
| Date: 2011-04-12 at 2:15PM |
| Venue: MSC E406 |
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| Abstract: For $q$ a power of a prime, consider the ring $\mathbb{F}_q[T]$. Due to the many similarities between $\mathbb{F}_q[T]$ and the ring of integers $\mathbb{Z}$, we can define for $\mathbb{F}_q[T]$ objects that are analogous to elliptic curves, modular forms, and modular curves. In particular, for $\mathfrak{p}$ a prime ideal in $\mathbb{F}_q[T]$, we can define the Drinfeld modular curve $X_0(\mathfrak{p})$, and study the reduction modulo $\mathfrak{p}$ of its Weierstrass points, as is done in the classical case by Rohrlich, and Ahlgren and Ono. In this talk we will present some partial results in this direction, defining all necessary objects as we go. |
| Title: Quasiisometric rigidity of some negatively curved solvable Lie groups |
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| Seminar: Analysis and Differential Geometry |
| Speaker: Xiangdong Xie of Georgia Southern University |
| Contact: Vladimir Oliker, oliker@mathcs.emory.edu |
| Date: 2011-04-12 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: We show that, for a class of negatively curved solvable Lie groups, every quasiisometry between them is an almost isometry, that is, it preserves the distance up to an additive constant. We prove this by studying the quasiconformal analysis on the ideal boundary. |
| Title: Multilevel Methods for Ill-Posed Problems |
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| Seminar: Numerical Analysis and Scientific Computing |
| Speaker: Lothar Reichel of Kent State University |
| Contact: Michelle Benzi, benzi@mathcs.emory.edu |
| Date: 2011-04-08 at 12:50PM |
| Venue: W306 |
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| Abstract: Multilevel methods for the solution of well-posed problems, such as certain boundary value problems for partial differential equations and Fredholm integral equations of the second kind, are popular and their properties are well understood. Much less is known about the behavior of multilevel methods for the solution of linear ill-posed problems, such as Fredholm integral equations of the first kind with a right-hand side that is contaminated by error. We discuss properties of cascadic multilevel methods for the latter kind of problems. |
| Title: The maximum size of a Sidon set contained in a sparse random set of integers |
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| Seminar: Combinatorics |
| Speaker: Sangjune Lee of Emory University |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2011-04-08 at 4:00PM |
| Venue: W306 |
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| Abstract: A set $A$ of integers is a \textit{Sidon set} if all the sums~$a_1+a_2$, with~$a_1\leq a_2$ and~$a_1$,~$a_2\in A$, are distinct. In the 1940s, Chowla, Erd\H{o}s and Tur\'an showed that the maximum possible size of a Sidon set contained in $[n]=\{0,1,\dots,n-1\}$ is $\sqrt{n}(1+o(1))$. We study Sidon sets contained in sparse random sets of integers, replacing the `dense environment'~$[n]$ by a sparse, random subset~$R$ of~$[n]$.\\ \\ Let~$R=[n]_m$ be a uniformly chosen, random $m$-element subset of~$[n]$. Let~$F([n]_m)=\max\{|S|\colon S\subset[n]_m\hbox{ Sidon}\}$. An abridged version of our results states as follows. Fix a constant~$0\leq a\leq1$ and suppose~$m=m(n)=(1+o(1))n^a$. Then there is a constant $b=b(a)$ for which~$F([n]_m)=n^{b+o(1)}$ almost surely. The function~$b=b(a)$ is a continuous, piecewise linear function of~$a$, not differentiable at two points:~$a=1/3$ and~$a=2/3$; between those two points, the function~$b=b(a)$ is constant. \\ \\ This is joint work with Yoshiharu Kohayakawa and Vojtech R\"odl. |
| Title: The Spread of Rabies in Raccoons: Numerical Simulations of a Spatial Diffusion Model |
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| Defense: Honors Thesis |
| Speaker: Joshua Keller of Emory University |
| Contact: Alessandro Veneziani, ale@mathcs.emory.edu |
| Date: 2011-04-07 at 10:30AM |
| Venue: N215 |
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| Abstract: |
| Title: Spatial Optimization of 4-Poster Feeders for Tick-Borne Disease Management |
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| Defense: Honors Thesis |
| Speaker: James Nance of Emory University |
| Contact: James Nagy, nagy@mathcs.emory.edu |
| Date: 2011-04-06 at 4:00PM |
| Venue: W306 |
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| Abstract: Amblyomma americanum, the Lone Star tick, is the predominant tick species throughout the southeast United States. Its significance as a threat to human health was not realized until recently. Recognized as an important disease vector, Amblyomma carry a serious bacteria, Ehrlichia chaffeensis, that causes human monocytic ehrlichiosis. In 1995, eleven cases of ehrlichiosis due to E. chaffeensis were identied in Faireld Glade, a retirement golf community near Crossivlle, Tennessee. The placement of "4-poster" acaricide feeders has been demonstrated to be a highly effective control method for eliminating Amblyomma populations. Here we formulate an economic criterion to evaluate various feeder placement scenarios within Faireld Glade that that minimize infected ticks and that tend toward future projects in optimization of this system. |
| Title: Bartle-Dunford-Schwartz Integration of scalar functions with respect to measures taking values in arbitrary topological vector spaces |
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| Seminar: Analysis and Differential Geometry |
| Speaker: Professor Iwo Labuda of The University of Mississippi |
| Contact: Michal Karonski, michal@mathcs.emory.edu |
| Date: 2011-04-05 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: Please see website for abstract. |
| Title: Subgraphs of large degree and large girth in graphs and digraphs |
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| Seminar: Combinatorics |
| Speaker: Daniel Martin of Universidade Federal do ABC |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2011-04-01 at 4:00PM |
| Venue: W306 |
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| Abstract: In 1983 Carsten Thomassen conjectured that for all positive integers $k$ and $g$ there exists $d$ such that all graphs with average degree at least $d$ contain a subgraph of average degree at least $k$ and girth at least $g$. In this talk we discuss what is known about this problem and its relationship with other problems. We also give a proof that the analogous problem for directed graphs has an affirmative answer. |