var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-31"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-29"><img src="//www2.math.ethz.ch/smsjs/images/arrow_right.png"/></a></div>    <div class="sms_title">      <span style="float: left;">SMS</span>      <span>SWISS MATHEMATICAL SOCIETY</span>      <span style="float: right;">SMG</span>    </div>    <div class="sms_info">      <span style="float: left; width: 250px;">Bulletin no. 2</span>      <span style="float: right; text-align:right; width: 250px;">23.9 - 27.9.2024</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Autumn Semester 2024</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, September 23      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Tom Mrowka (Massachusetts Institute of Technology)</div><div class="event_title">Floer homology of three manifolds and applications to low dimensional topology <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Floer homology and the related invariants of 4-manifolds has given us deep insight in smooth differential topology in dimensions 3 and particularly 4. The theory has yielded insights like existence of exotic differentiable structures on 4 dimensional euclidean space, complex curves minimize genus in complex projective space, killing the Hauptvermuntung, there even appear to be connection to the 4 color map theorem. This course will build up Floer homology of three manifolds from scratch. The focus will be on Instanton Floer homology but we will mention other versions and develop applications as the course goes on.</div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Oliver Edtmair (ETH)</div><div class="event_title">Systoles of convex energy hypersurfaces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Hofer-Wysocki-Zehnder proved that every strictly convex energyhypersurface in R^4 possesses a disk-like global surface of section. Theyasked whether a systole, i.e. a periodic orbit of least action, must spansuch a disk-like global surface of section. In my talk, I will give anaffirmative answer to this question. Moreover, I will discuss someimplications of this result concerning normalized symplectic capacities.This is based on joint work in progress with Abbondandolo and Kang.</div><div class="event_time">15:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1 + Note special room!</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://sites.google.com/view/pm-seminar/home">Physical Mathematics Seminar</a></div><br /><div class="event_speaker"> Hong-Quan  Tran  (Geneva)</div><div class="event_title"> Information percolation and mixing times of the Glauber-Exclusion process <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Glauber-Exclusion process, an interacting particle system introduced by De Masi, Ferrari, and Lebowitz, is a superposition of a Glauber dynamics and the symmetric simple exclusion process (SSEP) on a lattice. It was shown to admit a reaction-diffusion equation as the hydrodynamic limit. In this talk, we introduce the information percolation framework invented by Lubetzky and Sly and explain how it can be used to study the mixing times of our process. After defining a notion of temperature regimes via the equation in the hydrodynamic limit, we prove cutoff for the attractive model in the high-temperature regime, analogous to the results of Lubetzky and Sly for the Glauber dynamics of the Ising model. Our results show a connection between the hydrodynamic limit and the mixing behavior of the large but finite system. </div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Mathematisches Kolloquium </a></div><br /><div class="event_speaker">Prof. Dr. Florian Richter (EPFL)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Multiplicative Number Theory from a dynamical perspective</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Multiplicative number theory is the study of prime numbers, factorizations, divisors, and other basic mathematical concepts related to the multiplicative structure of the integers. The focus of this lecture lies on some of the newly emerging interfaces between multiplicative number theory and ergodic theory, which has led to significant advancements in recent years. We will provide an overview of the latest developments and explore some of the new methods and applications that have emerged.</div><div class="event_time">17:15 &bull; Universität Bern, Sidlerstrasse 5, 3012 Bern, Room 228</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, September 24      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Bachir Bekka (Université de Rennes)</div><div class="event_speaker"> Alessandra Iozzi (ETH Zürich)</div><div class="event_speaker"> Yves Benoist (Université de Rennes)</div><div class="event_speaker"> Serge Cantat (CNRS et Université de Renne)</div><div class="event_title"><a class="external" href="https://www.unige.ch/math/annonces/groupes-geometrie/journee-en-honneur-des-80-ans-de-pierre-de-la-harpe">Journée en honneur des 80 ans de Pierre de la Harpe </a></div><div class="event_time">09:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Gigliola Staffilani (Massachusetts Institute of Technology)</div><div class="event_title">Dispersive equations and wave turbulence theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this course we will investigate questions of weak turbulence theory by using as explicit example of wave interactions the solutions to periodic and nonlinear Schrödinger equations. We will start with Strichartz estimates on periodic setting, then we will move to well-posedness.We will then present two different ways of introducing the evolution of the energy spectrum. We will first work on a method proposed by Bourgain and involving the growth of high Sobolev norms. Then, we will give some ideas of how to derive rigorously the effective dynamics of the energy spectrum itself (wave kinetic equation), when one considers weakly nonlinear dispersive equations.  </div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Daniel Ruprecht (Technische Universität Hamburg)</div><div class="event_title">Recent results on spectral deferred corrections, parallel and otherwise <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Spectral deferred corrections (SDC) remain an underutilized approach for solving initial value problems. SDC can be considered a preconditioned, iterative solver for the collocation problem arising in a fully implicit Runge-Kutta method with a dense Butcher table. The key trick in SDC is that each iteration, or sweep, only requires stepping through the nodes with a simple, low order method like implicit Euler. In that way, SDC provide a framework to build methods of arbitrary high order out of simple, low order methods.SDC-based methods have many advantages. They typically come with large stability domains, easily tunable order of accuracy and are often more accurate than RKM of similar order when using comparable time step sizes. However, they require more right hand side evaluations per step than RKM (sometimes a lot more) and can only be computationally efficient if they allow a user to take much larger step sizes than RKM. In the talk, I will present recent work aiming to increase the computational efficiency of SDC. This will include approaches to parallelize SDC "across-the-method" to allow the use of small-scale parallelism to reduce the wallclock time of iterations. I will also show how the iterative structure of SDC can easily be exploited to construct a form of embedded method that can be used for step size control. Finally, I will comment one ongoing work regarding the use of reduced asymptotic coarse models to speed up SDC convergence as well as attempts to use physics-informed neural operators (PINO) to generate accurate starting values.This is joint work with J. Fregin, T. Lunet, I. Akramov, P. Freese, S. Götschel (TUHH), G. &#268;aklovic (KIT), T. Baumann (FZ Jülich) and M. Schreiber (Grenoble).</div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/daco-seminar">DACO Seminar</a></div><br /><div class="event_speaker"> Vanessa Piccolo (ENS Lyon, FR)</div><div class="event_title">Dynamics of optimization in high dimensions for multi-spiked tensor PCA <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will study the high-dimensional statistical problem of multi-spiked tensor PCA, where the goal is to infer a finite number of unknown, orthogonal signal vectors (or spikes) from noisy observations of a p-tensor. I will present our recent results on the sample complexity required for stochastic gradient descent to efficiently recover the signal vectors from natural initializations. In particular, we will show that it is possible to recover a permutation of all spikes provided a number of sample scaling as N^{p-2}, aligning with the computational threshold identified in the rank-one tensor PCA problem. The recovery process is governed by a sequential elimination phenomenon. As one correlation exceeds an explicit critical threshold, all correlations that share a row or column index become sufficiently small to be negligible, allowing the subsequent correlation to grow and become macroscopic. The order in which correlations become macroscopic is determined by their initial values and the associated signal-to-noise ratios. Based on recent joint work with Gérard Ben Arous (NYU) and Cédric Gerbelot (NYU).</div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://calendar.google.com/calendar/embed?mode=AGENDA&height=600&wkst=2&bgcolor=%23FFFFFF&src=t36it03v52cus2detrvinlgk18%40group.calendar.google.com&color=%235F6B02&ctz=Europe%2FZurich">Groups, Arithmetic and Algebraic Geometry Seminar </a></div><br /><div class="event_speaker"> Anshul Adve</div><div class="event_title">Density criteria for Fourier uniqueness phenomena in R^d <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A remarkable byproduct of the work of Viazovska et al. on sphere packing is the notion of a "Fourier uniqueness set": a discrete subset A of R^d such that any Schwarz function on R^d is determined by its restriction and the restriction of its Fourier transform to A. Once one knows such sets exist, it is natural to ask how dense they must be / how sparse they can be. This was determined in dimension 1 by Kulikov, Nazarov, and Sodin, but the higher dimensional story was much less well understood. We will give an answer in all dimensions using new methods.</div><div class="event_time">14:15 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Dr. Jaume De Dios Pont (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">Log-concave measures can have interior hot spots <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let u(x,t) be the temperature distribution of a d-dimensional convex domain at time t with given initial temperature u(x,0) and insulating boundary. The hot-spots conjecture of Rauch asserts that for large times, the maximum of the function x -> u(x,t) is taken near the boundary of the domain.Equivalently, the conjecture asserts that the first nontrivial Neumann Laplace eigenfunction of a convex domain takes its maximum (and minimum) in the boundary.A general philosophy in convex analysis is that dimension free statements about convex sets imply an analogous, dimension-free statement about log-concave measures.In this talk I will construct the log-concave analogue to the hot spots conjecture, and construct a counterexample for it in high dimensions.</div><div class="event_time">15:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/colloque">Colloque de Mathématiques </a></div><br /><div class="event_speaker"> Serge Cantat  (CNRS et Université de Rennes)</div><div class="event_title">Croissance du groupe de Cremona <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Le groupe de Cremona est formé de toutes les transformations birationnelles du plan, c’est-à-dire les transformations inversibles qui s’expriment - ainsi que leur inverse - à l\'aide de fractions rationnelles en les coordonnées cartésiennes. Je décrirai ce groupe en me concentrant sur la notion de croissance.<br>Ce colloque fait partie du Séminaire Groupes et Géométrie qui tiendra une session spéciale à l’occasion des 80 ans de de Pierre de la Harpe.<br>De plus, que pour des raisons logistiques, l\'inscription est nécessaire avant le 20 septembre.</div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/zurich-colloquium-in-mathematics">Zurich Colloquium in Mathematics</a></div><br /><div class="event_speaker"> Rupert Frank  (Universität München )</div><div class="event_title">The Wehrl entropy problem: mathematical physics meets complex analysis and representation theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The coherent state transform, under various names, appears in many fields of mathematics and physics. It is associated with representations of a group. In this talk we are concerned with the problem of minimizing the entropy of the coherent state transform and we explain how complex analysis can be used to achieve this in certain settings. We discuss various open questions</div><div class="event_time">16:30 &bull; UZH Zentrum, Building KO2, Room F  150</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, September 25      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Prof. Dr. Adam Kanigowski (University of Maryland)</div><div class="event_title">Horocycle flows at semi-prime times <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this joint work with G. Forni and M. Radziwill we study the orbits of horocycle flows when sampled at semi-primes (integers with at most two prime factors). We show that if the lattice is arithmetic then such orbits equidistribute towards Haar measure for every non-periodic point. During the talk I will outline a new criterion for semi-primes, and describe main ideas of the proof.</div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker"> William Newman (Ohio State University)</div><div class="event_title">Chow groups of moduli spaces via higher Chow groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />One can use Bloch\'s higher Chow groups to compute the usual Chow groups of moduli spaces. This involves first computing the necessary higher Chow groups, and then computing the connecting homomorphism of the localization exact sequence. I will explain general techniques for performing these computations and give examples for the integral Chow groups of moduli spaces of genus 1 curves.</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">Jens Kopp</div><div class="event_title">Code-Based Cryptography and Algebraic Geomtry Codes</div><div class="event_time">15:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/sam/news-and-events/zhacm-colloquia">Zurich Colloquium in Applied and Computational Mathematics</a></div><br /><div class="event_speaker">Dr. Martin Averseng (Université d’Angers)</div><div class="event_title">Non-manifold boundary element methods <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Boundary Element Method (BEM) is a discretization technique commonly employed for the accurate and rapid numerical solution of constant-coefficient second-order partial differential equations (PDEs) in the complement of an obstacle, e.g., electromagnetic scattering problems. The BEM exploits the fundamental solution of the PDE to reduce the number of unknowns compared to the Finite Element Method for the same level of error. However, it is a non-local method and thus leads to full linear systems. For this reason, the BEM linear systems are often solved iteratively, and good preconditioners often turn out to be a key ingredient to ensure a fast resolution. In this talk, we present the motivation and the practical and mathematical challenges for extending the BEM to geometric settings involving non-manifold boundaries. We will first summarize the recent advances in the mathematical formalization of this problem. We will then present a particular preconditioning technique for "multi-screen" obstacles based on substructuring (domain decomposition). This work is in collaboration with Xavier Claeys and Ralf Hiptmair.</div><div class="event_time">16:00 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://memento.epfl.ch/event/probability-and-stochastic-analysis-seminar/">Probability (and Stochastic Analysis) Seminar </a></div><br /><div class="event_speaker"> David  Nualart  (University of Kansas)</div><div class="event_title">Malliavin calculus and tightness of probability measures <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The purpose of this talk is to discuss the applications of the stochastic calculus of variations or Malliavin calculus to proving  tightness in the context of functional central limit theorems.  The moment estimates that imply the required tightness property  are obtained using Meyer’s inequalities and a suitable representation of centered random variables as the divergence of a random field. We will apply this approach to the asymptotic behavior of the renormalized self-intersection local time of a d-dimensional fractional Brownian motion and to the Breuer-Major theorem for functionals of a stationary Gaussian process. </div><div class="event_time">16:15 &bull; EPF Lausanne, MA B2 485</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">Prof. Dr. Julia Lieb (Institut für Mathematik, TU Ilmenau)</div><div class="event_title">On a class of convolutional codes with optimal column distances and efficient decoding algorithm <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />There exist Singleton-like upper bounds for the column distances of convolutional codes, which can be reached if the underlying finite field is sufficiently large. However, it is not known which field size is necessary to reach these bounds and known code constructions require very large field sizes. In the first part of this talk, we inverse this construction problem by fixing the field and investigating what column distances are possible over the given field. In this way we construct binary convolutional codes with maximal column distances among all binary convolutional codes with the same code parameters. Furthermore, as these optimal binary convolutional codes turn out to be related to binary first-order Reed-Muller block codes, we can use this to develop an efficient decoding algorithm for these convolutional codes. This algorithm is a reduced complexity version of the Viterbi algorithm and hence it is a maximum likelihood algorithm. Finally, we generalize the presented construction of optimal binary convolutional codes to arbitrary finite fields, i.e. for some code rates and fixed arbitrary finite field, we obtain a construction of convolutional codes with optimal column distances.</div><div class="event_time">16:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://ethz.ch/en/news-and-events/events/inaugural-farewell-introductory-lectures.html">Inaugural Lectures</a></div><br /><div class="event_speaker">Prof. Dr. Svitlana Mayboroda (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">The hidden structure of the disorder: seeing complex geometry through the goggles of waves and minimizers</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room F 30</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, September 26      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Uri Feige</div><div class="event_title"> Fair allocations with little communication <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We study the multi-party randomized communication complexity of computing a fair allocation of m indivisible goods to n equally entitled agents. We first consider allocations that give every agent at least her maximin share (MMS). Such allocations are guaranteed to exist for simple classes of valuation functions. We show how a seemingly small change in the class of valuation functions leads to an exponential jump in the expected number of bits that an agent needs to transmit (on average over all agents).  For general additive valuations, MMS allocations need not exist. Hence, we consider two alternative relaxed fairness notions that are feasible. We demonstrate a nearly exponential gap between their expected average communication complexities. Our work leaves open interesting questions, some concerning the analysis of simple randomized algorithms, and some concerning lower bound techniques.</div><div class="event_time">11:00 &bull; EPF Lausanne, BC 01</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Guillaume  Bertoli (ETH Zürich)</div><div class="event_title">ML-based radiative transfer parameterization in the ICON climate model <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />As climate modellers prepare their code for kilometre-scale global simulations, the computationally demanding radiative transfer parameterization is a prime candidate for machine learning (ML) emulation. This project contributes to the discussion on how to incorporate physical constraints into an ML-based radiative parameterization,and how different neural network (NN) designs and output normalization affect prediction performance. A random forest is used as a baseline method, with the European Centre for Medium-Range Weather Forecasts (ECMWF) model ecRad, the operational radiation scheme in the Icosahedral Nonhydrostatic Weather and Climate Model (ICON), used for training. For the best emulator, we use a recurrent neural network architecture which closely imitates the physical process it emulates.We additionally normalize the shortwave and longwave fluxes to reduce their dependence from the solar angle and surface temperature respectively. Finally, we train the model with an additional heating rates penalty in the loss function. Because ICON top height layers are artificial sponge layers, we use an idealized formula to infer the radiation there. We perform a one month ICON simulation with an ML radiation emulator and compare it to a simulation with ecRad. The simulation with the ML solver remains accurate while the computation of the entire simulation is up to 3x faster. The machine learning emulator does not seem to affect the stability of ICON on longer simulations.</div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/talks-in-financial-and-insurance-mathematics">Talks in Financial and Insurance Mathematics</a></div><br /><div class="event_speaker">Prof. Dr. Rama Cont (University of Oxford)</div><div class="event_title">Itô calculus without probability <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />It was shown by Hans Föllmer that the Ito formula may be derived as an analytical change of variable formula for smooth functions of irregular trajectories with finite quadratic variation, without making use of any probabilistic methods. We show how this idea may be pushed farther to construct an Ito calculus for  causal functionals of irregular paths with finite (and non-zero) p-th order variation for any p>1. In particular we will discuss pathwise integration and change of variable formulae for functionals of irregular trajectories,  as well as pathwise analogues of martingales and Doob-Meyer decompositions. These results have natural applications to pathwise optimal control and model-free formulations in mathematical finance.References: R Cont, R Jin (2024) Fractional Ito calculus, Transactions of the American Mathematical Society, Ser. B 11, 727-761.H Chiu, R Cont (2022) Causal Functional Calculus. Transactions of the London Mathematical Society, Volume 9, No. 1 December 2022, 237-269.R Cont, N Perkowski (2019) Pathwise integration and change of variable formulas for continuous paths with arbitrary regularity, Transactions of the American Mathematical Society (Series B), Volume 6, 161-186.</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, September 27      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/tggroup/doku.php?id=fables">Séminaire "Fables Géométriques" </a></div><br /><div class="event_speaker"> Anatoly  Libgober  (University of Illinois, Chicago)</div><div class="event_title">Some applications of elliptic genus <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I discuss the role of elliptic genus in the study of geometric problems, including complex cobordisms, study of birational classes of algebraic varieties and mirror correspondence. As an application of an equivariant version of elliptic genus I also discuss the LG/CY correspondence.</div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://calendar.google.com/calendar/embed?mode=AGENDA&height=600&wkst=2&bgcolor=%23FFFFFF&src=t36it03v52cus2detrvinlgk18%40group.calendar.google.com&color=%235F6B02&ctz=Europe%2FZurich">Groups, Arithmetic and Algebraic Geometry Seminar </a></div><br /><div class="event_speaker"> Junecue Suh (University of California, Santa Cruz)</div><div class="event_title">Geometry in Bruhat-Tits buildings and p-adic representations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> In finite group theory and number theory, one is interested in the representations of finite groups or the (profinite) Galois groups of number fields, with coefficients in p-adic fields such as Q_p.  While they can be studied purely algebraically (e.g. in the style of Brauer, Green, Thompson and others), other mathematicians (at least since the work of Serre on trees) have used the Bruhat-Tits buildings to study them.  Namely, one studies the locus fixed (pointwise) by the group action.  I intend to report on some recent progress, which depends on an index theorem of Gauss-Bonnet type, when the locus has 2 dimensions.</div><div class="event_time">14:15 &bull; EPF Lausanne, GA 3 34</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker"> Max Schimpf (Universität Heidelberg)</div><div class="event_title">Stable pairs on local curves and Bethe roots <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Local curves are an important class of threefolds which are indicative of the general behaviour of curve counting invariants. We give a closed formula for all descendent stable pair invariants of (absolute) local curves and use these to prove structure results conjectured by Pandharipande and Pixton. We then use our results to give a new approach to the Bethe ansatz story in physics/representation theory.</div><div class="event_time">16:00 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>      </div>    </div>  </div>  <div id="sms_footer">    address: Alessandra Naldi Windler, Departement Mathematik, HG G 51.4, ETH Zurich, Raemistrasse 101, CH-8092 Zurich<br />    email: <a href="mailto:bulletin@math.ch">bulletin@math.ch</a> | phone: +41 44 632 3684 | url: <a href="https://math.ch">https://math.ch</a>    <br /><br /><img src="//www2.math.ethz.ch/smsjs/sms_logo.gif" width="150" alt="SMS/SMG Logo" title="SMS/SMG Logo" />  </div></div>';