D-MATH Weekly BulletinNews and Events (in particular 'Research Seminars') at D-MATH, ETH Zurichen-us
http://www.fim.math.ethz.ch/bulletin
Wed, 02 Dec 2015 02:28:44 +010060Dustin Ross - Applications of Axiomatic Gromov-Witten Theory II<h2 color="grey">Algebraic Geometry and Moduli Seminar</h2><h1>Applications of Axiomatic Gromov-Witten Theory II</h1><br /><font color="grey">Speaker:</font> Dr. Dustin Ross, Uniersity of Michigan<br /><font color="grey">Location:</font> HG G 43 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 2 December 2015 @ 13:30<br /><br /><strong>Abstract:</strong><br />In this three-part lecture series, I will describe Givental's axiomatic framework for studying GW theory, along with various problems to which the setup is particularly well-suited. The first two lectures will be devoted to a discussion of Givental's formalism, along with a survey of applications including mirror symmetry, the crepant transformation conjecture, and quasi-map wall-crossing. This survey spans twenty years of research in GW theory. In the third lecture, I will discuss recent work with Emily Clader in which we apply a number of the previously discussed tools to generalize the Landau-Ginzburg/Calabi-Yau correspondence beyond hypersurfaces.http://www.math.ethz.ch/screen/info?guid=7483Tue, 24 Nov 2015 10:54:43 +0100Martino Borello - On the Stabilizer of Weight Enumerators of Linear Codes abstract<h2 color="grey">Arbeitsgemeinschaft in Codierungstheorie und Kryptographie (uzh)</h2><h1>On the Stabilizer of Weight Enumerators of Linear Codes abstract</h1><br /><font color="grey">Speaker:</font> Martino Borello, Ecole Polytechnique Federale de Lausanne<br /><font color="grey">Location:</font> Uni Neuchatel, B217<br /><font color="grey">Start Date/Time:</font> 2 December 2015 @ 15:00http://www.math.ethz.ch/screen/info?guid=8105Tue, 30 Nov 1999 00:00:00 +0100Mentor Stafa - Spaces of commuting elements in Lie groups<h2 color="grey">Geometry Seminar</h2><h1>Spaces of commuting elements in Lie groups</h1><br /><font color="grey">Speaker:</font> Mentor Stafa, ETH Zurich<br /><font color="grey">Location:</font> HG G 43 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 2 December 2015 @ 15:45<br /><br /><strong>Abstract:</strong><br />The spaces of group homomorphisms Hom(A,B) have been studied in various contexts. We study the space of pairwise commuting n-tuples in a compact and connected Lie group G, from the topological viewpoint. We will give a brief survey of recent work on these spaces as well as tools to compute their homology with certain coefficients, possibly the ring of integers. Among the tools are various stable decompositions of spaces of homomorphisms into the wedge sum of smaller spaces.http://www.math.ethz.ch/screen/info?guid=7982Mon, 30 Nov 2015 11:39:15 +0100Anna-Lena Horlemann - title t.b.a.<h2 color="grey">Arbeitsgemeinschaft in Codierungstheorie und Kryptographie (uzh)</h2><h1>title t.b.a.</h1><br /><font color="grey">Speaker:</font> Dr. Anna-Lena Horlemann, Ecole Polytechnique Federale de Lausanne<br /><font color="grey">Location:</font> Uni Neuchatel, B217<br /><font color="grey">Start Date/Time:</font> 2 December 2015 @ 16:00http://www.math.ethz.ch/screen/info?guid=8106Tue, 01 Dec 2015 14:00:11 +0100Guido Kanschat - Asymptotically Correct Discontinuous Galerkin Methods for Radiation Transport<h2 color="grey">Zurich Colloquium in Applied and Computational Mathematics</h2><h1>Asymptotically Correct Discontinuous Galerkin Methods for Radiation Transport</h1><br /><font color="grey">Speaker:</font> Prof. Dr. Guido Kanschat, University Heidelberg, Germany<br /><font color="grey">Location:</font> Y27 H 25 (UZH Irchel)<br /><font color="grey">Start Date/Time:</font> 2 December 2015 @ 16:15<br /><br /><strong>Abstract:</strong><br />While discontinuous Galerkin (DG) methods had been developed and analyzed in the 1970s and 80s with applications in radiative transfer and neutron transport in mind, it was pointed out later in<br />the nuclear engineering community, that the upwind DG discretization by Reed and Hill may fail to produce physically relevant approximations, if the scattering mean free path length is smaller<br />than the mesh size. Mathematical analysis reveals, that in this case, convergence is only achieved in a continuous subspace of the finite element space. Furthermore, if boundary conditions are not chosen<br />isotropically, convergence can only be expected in relatively weak topology. While the latter result is a property of the transport model, asymptotic analysis reveals, that the forcing into a continuous<br />subspace can be avoided. By choosing a weighted upwinding, the conditions on the diffusion limit can be weakened. It has been known for long time, that the so called diffusion limit of radiative<br />transfer is the solution to a diffusion equation; it turns out, that by choosing the stabilization carefully, the DG method can yield either the LDG method or the method by Ern and Guermond in its<br />diffusion limit. Finally, we will discuss an efficient and robust multigrid method for the resulting discrete problems.http://www.math.ethz.ch/screen/info?guid=7065Sat, 07 Nov 2015 18:15:02 +0100Alain Rouault - Sum rules via large deviations<h2 color="grey">Seminar on Stochastic Processes</h2><h1>Sum rules via large deviations</h1><br /><font color="grey">Speaker:</font> Alain Rouault , Versailles<br /><font color="grey">Location:</font> HG G 43 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 2 December 2015 @ 17:15<br /><br /><strong>Abstract:</strong><br />In the theory of orthogonal polynomials, sum rules are remarkable relationships between a functional defined on a subset of all probability measures involving the reverse Kullback-Leibler divergence with respect to a particular distribution and recursion coefficients related to the orthogonal polynomial construction. I will give a short historical introduction, from Szegö until<br />Killip and Simon and descendants. These last authors proved in 2003 a quite surprising sum rule for measures dominating the semicircular distribution on $[-2,2]$. This sum rule includes a contribution of the atomic part of the measure away from $[-2,2]$. It is posssible to recover this sum rule by using large deviations on random matrices and on their extremal eigenvalues. This method allows to obtain new sum rules, when the reference measure is the Marchenko-Pastur or Kesten-McKay distribution. These formulas include a contribution of the atomic part appearing away from the support of the reference measure; (joint work with F. Gamboa and J. Nagel).http://www.math.ethz.ch/screen/info?guid=7472Thu, 26 Nov 2015 13:33:11 +0100Walter Schachermayer - The asymptotic theory of transaction costs<h2 color="grey">Nachdiplomvorlesung</h2><h1>The asymptotic theory of transaction costs</h1><br /><font color="grey">Speaker:</font> Prof. Dr. Walter Schachermayer, ETH-ITS / Universität Wien<br /><font color="grey">Location:</font> HG G 43 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 3 December 2015 @ 10:15<br /><br /><strong>Abstract:</strong><br />In the traditional no arbitrage theory, which goes back to the seminal work of Black, Scholes,<br />and Merton in the late sixties, one of the idealizing assumptions pertains to the absence of<br />transaction costs. In this classical theory one simply assumes that at any moment of time there<br />is one price for the underlying asset at which one may sell or buy.<br />Since these pioneering papers there is quite some literature on the effects which arise if one<br />deviates from this mathematically convenient but practically sometimes misleading assumption<br />of a frictionless market.<br />In the Nachdiplomvorlesung I shall review these results and will put emphasis on the asymptotic<br />effects when proportional transaction costs are small, but different from zero. Special<br />focus will be given to a series of recent papers with Christoph Czichowsky on this theory. In<br />the course we shall also encounter some challenging issues in stochastc analysis arising from<br />the problems arising in the theory of portfolio optimization under small transaction costs.<br />http://www.math.ethz.ch/screen/info?guid=7853Tue, 13 Oct 2015 10:25:07 +0200Hanno Becker - "Homotopy-theoretic studies of Khovanov-Rozansky Homology"<h2 color="grey">Talks in Mathematical Physics</h2><h1>"Homotopy-theoretic studies of Khovanov-Rozansky Homology"</h1><br /><font color="grey">Speaker:</font> Hanno Becker, Bonn<br /><font color="grey">Location:</font> HG G 43 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 3 December 2015 @ 15:15<br /><br /><strong>Abstract:</strong><br />"This talk is a summary of the results of my PhD project<br />(written at the University of Bonn under supervision of Catharina<br />Stroppel) the aim of which was to use homotopy theoretic methods to<br />understand better Khovanov-Rozansky homology, a categorification of the<br />quantum sl(k) link invariant constructed using categories of matrix factorizations.<br /><br />I will start by recalling the relevant definitions for matrix<br />factorizations and the original construction of KR homology. Afterwards, I will explain a notion of weak equivalences for matrix factorizations (for<br />which no notion of homology is available) such that with respect to this,<br />the complexes assigned to braids in Khovanov-Rozansky homology are<br />component-wise weakly equivalent to the respective Rouquier complexes of Soergel bimodules. In particular, we get a description of KR homology as stable Hochschild homology of Rouquier complexes, parallel to Khovanov's<br />description of triply graded KR homology via ordinary Hochschild homology.<br />As another application, I will define a combinatorial cut-and-join<br />formalism - similar to the one used in the construction of Khovanov homology - computing an approximation of KR homology, allowing to calculate KR homology in simple cases."<br />http://www.math.ethz.ch/screen/info?guid=7769Fri, 20 Nov 2015 11:39:40 +0100 Kristine Barro-Bergflödt - Quaternionen oder der Gürteltrick von Dirac<h2 color="grey">Kolloquium über Mathematik, Informatik und Unterricht</h2><h1>Quaternionen oder der Gürteltrick von Dirac</h1><br /><font color="grey">Speaker:</font> Kristine Barro-Bergflödt, ETH Zürich<br /><font color="grey">Location:</font> HG G 3 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 3 December 2015 @ 17:15<br /><br /><strong>Abstract:</strong><br />Kaum finden sich die Schülerinnen und Schüler im abstrakten Neuland der komplexen Zahlen einigermassen zurecht, kommt bei manchen der Hunger nach mehr und sie stellen wie schon Hamilton die tiefe mathematische Frage: Was kommt nach den komplexen Zahlen? Der Vortrag wirft ein Licht auf die Geschichte der Quaternionen, ihre Beziehung zu räumlichen Rotationen und die Frage nach weiteren "Zahlen".http://www.math.ethz.ch/screen/info?guid=7042Mon, 02 Nov 2015 10:55:48 +0100David Dickson - Analysis of a risk model with capital injections<h2 color="grey">Talks in Financial and Insurance Mathematics</h2><h1>Analysis of a risk model with capital injections</h1><br /><font color="grey">Speaker:</font> David Dickson, Melbourne University<br /><font color="grey">Location:</font> HG G 43 (ETH Zentrum)<br /><font color="grey">Start Date/Time:</font> 3 December 2015 @ 17:15<br /><br /><strong>Abstract:</strong><br />We consider a risk model under which the insurer purchases a reinsurance contract that provides capital injections. These capital injections restore the surplus process to a fixed level, k, every time the surplus falls between 0 and k. In the first part of the talk we briefly discuss the effect of capital injections on the insurer's ultimate ruin probability. In the second part, we discuss calculation of the finite time ruin probability under this model, and show how to find the density of the time of ruin when the claim size distribution is exponential. We then construct a Gerber-Shiu function and find an interesting formula for the finite time survival probability.http://www.math.ethz.ch/screen/info?guid=7548Tue, 17 Nov 2015 15:37:20 +0100Michael Loss - [Video Seminar] The phase diagram of the Caffarelli-Kohn-Nirenberg inequalities<h2 color="grey">Seminar PDE and Mathematical Physics (uzh)</h2><h1>[Video Seminar] The phase diagram of the Caffarelli-Kohn-Nirenberg inequalities</h1><br /><font color="grey">Speaker:</font> Prof. Dr. Michael Loss, Georgia Tech<br /><font color="grey">Location:</font> Y27 H 35/36 (UZH Irchel)<br /><font color="grey">Start Date/Time:</font> 3 December 2015 @ 18:10http://www.math.ethz.ch/screen/info?guid=7241Thu, 26 Nov 2015 07:00:09 +0100