All Seminars
| Title: The pretentious view of analytic number theory |
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| Seminar: Algebra |
| Speaker: Robert Lemke Oliver of Emory University |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2013-01-23 at 3:00PM |
| Venue: W306 |
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| Abstract: Analytic number theory was borne out of the desire to understand the distribution of the primes. In particular, much of modern analytic number theory can trace its origins to Riemann's seminal 1859 memoir, in which he outlines an attack on the prime number theorem by means of the study of the zeros of what we now call the Riemann zeta function. This approach has been fruitful, and has given rise to a lot of beautiful mathematics, but this hides the dirty truth of analytic number theory: what we can prove, and what we believe to be true, are incredibly far apart. What's more, the best known zero-free region is more than fifty years old. In other words, analytic number theory is in dire need of new ideas. The pretentious view of analytic number theory, as put forward by Granville and Soundararajan, is an attempt at doing this; it is analytic number theory without zeros of L-functions and without analytic continuation. As a substitute, Granville and Soundararajan propose a general study of multiplicative functions, with the goal being to obtain deep structure theorems from which arithmetic results arise as corollaries; as such, it can be seen as finally establishing the context for the elementary proof of the prime number theorem developed by Erdos and Selberg. In this talk, we ask about the structure of functions exhibiting more cancellation than they have a right to. We are able to completely classify such functions in a natural setting, and we establish the right context to consider this question pretentiously. Moreover, as pretentiousness is still a young theory, we outline our vision of what the future holds and what we believe to be the major outstanding questions. This talk is a practice job talk, so feedback would be greatly appreciated. |
| Title: Visibility of Torsors of an Abelian Variety |
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| Seminar: Algebra and Number Theory |
| Speaker: Saikat Biswas of Georgia Tech |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2013-01-16 at 3:00PM |
| Venue: W306 |
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| Abstract: We survey results that uses the theory of visibility developed by Mazur to study torsors (global as well as local) associated to an abelian variety. |
| Title: Topological and Functional Properties of Proteins in Protein-Protein Interaction Networks |
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| Seminar: Numerical Analysis and Scientific Computing |
| Speaker: Concettina Guerra of College of Computing, Georgia Institute of Technology, USA |
| Contact: Michele Benzi, benzi@mathcs.emory.edu |
| Date: 2012-12-05 at 12:50PM |
| Venue: W306 |
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| Abstract: I will discuss the connection between the topological properties of proteins in Protein-Protein Interaction (PPI) networks and their biological relevance focusing on hubs, i.e. proteins with a large number of interacting partners. In particular, the following questions will be addressed: Do hub proteins tend to be more essential than non-hub proteins? Do they play a central role in modular organization of the protein interaction network? Are they more evolutionarily conserved? Are there structural properties that characterize hub proteins? I will then present recently developed algorithms for identifying groups of highly connected proteins, or complexes, that are evolutionary conserved. Given the networks of two organisms, the algorithms uncover sub-networks of proteins that relate in biological function and topology of interactions. The discovered conserved sub-networks have a general topology and need not to correspond to specific interaction patterns, so that they more closely fit the models of functional complexes proposed in the literature. |
| Title: Crystalline cohomology of the Igusa tower and families of ordinary cuspforms |
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| Seminar: Algebra and Number Theory |
| Speaker: Bryden Cais of University of Arizona |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-12-05 at 3:00PM |
| Venue: W306 |
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| Abstract: We explain a relation between the crystalline cohomology of the Igusa tower and the Iwasawa module of ordinary Lambda-adic cusp forms. By studying the de Rham cohomology of Igusa curves in characteristc p, we will use this relation to give a new proof of the existence of ordinary families of cuspforms. |
| Title: Sensor Web: Research Challenges and Opportunities |
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| Seminar: Computer Science |
| Speaker: WenZhan Song of Georgia State University |
| Contact: Vaidy Sunderam, vss@emory.edu |
| Date: 2012-11-30 at 3:00PM |
| Venue: MSC W301 |
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| Abstract: In this talk, we will discuss several research challenges and opportunities of sensor web in environment monitoring, smart grid and smart environment. Several years ago, we designed and deployed the first space in-situ sensor web in Mount St. Helens collaborating with USGS and JPL in a NASA ESTO project. We are currently advancing this research agenda to create a new paradigm, VolcanoSRI (Volcano Seimic Realtime Imaging), for imaging the 4D volcano tomography in a large-scale sensor network, joint with UNC and MSU in a NSF CDI project. A future effort aims to integrate seismic tomography, InSAR and deformation model to make the fictional holographic projector known as Virgil in the film "Supervolcano" a reality. We are also collaborating with Cornell and UC Berkerley to investigate several key aspects of a computation and information foundation of the smart grids in a NSF CPS project. We are studying distributed demand and response algorithms and designing an open and scalable experimental platform for smart grid, known as SmartGridLab, that integrates a hardware testbed with a software emulator, allowing software virtual nodes to interact with physical nodes in the testbed. We also discusses several research opportunities on smart environments, with the goal of enabling smart healthcare and ambient intelligence. |
| Title: Gossip-based distributed matrix computations |
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| Seminar: Scientific Computing Seminar |
| Speaker: Hana Strakova of University of Vienna and GA Tech |
| Contact: TBA |
| Date: 2012-11-28 at 12:50PM |
| Venue: W306 |
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| Abstract: Truly distributed matrix computations with randomized communication schedules, such as gossip-based algorithms, can offer many attractive properties. Due to their randomized communication restricted only to direct neighbors they are very flexible with respect to the underlying hardware infrastructure. They can operate on arbitrary topologies and they can be made resilient against dynamic changes in the network, against message loss or node failures, and against asynchrony between compute nodes. Moreover, their overall cost can be reduced by accuracy-communication trade-offs. Such properties are attractive especially for loosely-coupled distributed systems with unreliable communication links, such as sensor or P2P networks. However, due to the growth in the number of nodes for future extreme-scale HPC systems and the anticipated decrease in reliability, some properties of gossip-based distributed algorithms may become important also for future HPC systems. We are investigating distributed algorithms for various prototypical matrix computation problems which utilize gossip-based aggregation algorithms for performing reduction operations in a distributed manner. Questions addressed relate to the (communication) cost paid for the increased flexibility and robustness, to convergence properties, to numerical accuracy achieved, as well as to the benefits of accuracy-communication cost trade-offs. |
| Title: A characterization of cusp forms by means of the growth of their Fourier coefficients |
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| Seminar: Algebra and Number Theory |
| Speaker: Winfried Kohnen of Heidelberg University |
| Contact: David Zureick-Brown, dzb@mathcs.emory.edu |
| Date: 2012-11-28 at 3:00PM |
| Venue: W306 |
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| Abstract: We will characterize elliptic cusp forms and also Siegel cusp forms of degree two by means of the growth of their Fourier coefficents. |
| Title: Introduction to GPU Computing: Basics of OpenCL |
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| Seminar SIAM Student Chapter: Numerical Analysis and Scientific Computing |
| Speaker: Veronica Mejia Bustamante of Emory University |
| Contact: Veronica Mejia Bustamante, vmejia@emory.edu |
| Date: 2012-11-27 at 4:00PM |
| Venue: W306 |
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| Abstract: The Emory SIAM Student Chapter is pleased to present an introductory seminar to GPU computing. The seminar is open to both graduate and undergraduate students interested in learning more about this growing field of scientific computing applications. This seminar will provide an introduction to GPU programming in both the hardware and software level. We will discuss the hardware setup of a GPU and the threads execution model. We will also cover the basics of the OpenCL API including the programming model and memory hierarchy and discuss easy techniques to begin writing your first GPU program in OpenCL. This will be an informal session, no previous GPU computing experience is required. Great food will be provided during the seminar! |
| Title: Induced and noninduced Ramsey numbers of $k$-partite, $k$-uniform hypergraphs |
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| Seminar: Combinatorics |
| Speaker: Steve La Fleur of Emory University |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2012-11-16 at 4:00PM |
| Venue: MSC W303 |
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| Abstract: Given two (hyper)graphs $S$ and $T$, the Ramsey number $r(S,T)$ is the smallest integer $n$ such that, for any two-coloring of the edges of $K_n$ with red and blue, we can find a red copy of $S$ or a blue copy of $T$. Similarly, the induced Ramsey number, $r_{\mathrm{ind}}(S,T)$, is defined to be the smallest integer $N$ such that there exists a (hyper)graph $R$ with the following property: In any two-coloring of the edges of $R$ with red and blue, we can always find a red \emph{induced} copy of $S$ or a blue \emph{induced} copy of $T$. In this talk we will discuss bounds for $r(K^{(k)}_{t,\dots,t}, K_s^{(k)})$ where $K^{(k)}_{t,\dots,t}$ is the complete $k$-partite $k$-graph with partition classes of size $t$. We also present new upper bounds for $r_{\mathrm{ind}}(S, T)$, where $T \subseteq K^{(k)}_{t,\dots,t}$ and $S \subseteq K_s^{(k)}$. |
| Title: An information theoretic approach to Sobolev and isoperimetric inequalities |
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| Colloquium: N/A |
| Speaker: Professor Deane Yang of NYU-Poly |
| Contact: Vladimir Oliker, oliker@mathcs.emory.edu |
| Date: 2012-11-15 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: I will describe connections among information theoretic, Sobolev-type, and isoperimetric inequalities and how these ideas can be used to establish new results. |