var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-38"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-36"><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. 7</span>      <span style="float: right; text-align:right; width: 250px;">30.10 - 3.11.2023</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Autumn Semester 2023</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, October 30      </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">Dr. Dominik Kwietniak (Jagiellonian University)</div><div class="event_title">An anti-classification theorem for the topological conjugacy of Cantor minimal systems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;BR> &lt;p align="justify"> The isomorphism problem in dynamics  dates back to a question of von Neumann from 1932: Is it possible to classify (in some reasonable sense) the ergodic measure-preserving diffeomorphisms of a compact manifold up to isomorphism? We want to study a similar problem: Let C be the Cantor set and let Min(C) stand for the space of all minimal homeomorphisms of the Cantor set. Recall that a homeomorphism f is in Min(C) if every orbit of f is dense in C.  We say that f and g in Min(C) are topologically conjugate if there is a Cantor set homeomorphism h such that f o h = h o g. We prove an anti-classification result showing that even for very liberal interpretations of what a "reasonable\'\' classification scheme might be, a classification of minimal Cantor set homeomorphism up to topological conjugacy is impossible. We see it as a consequence of the following: we prove that the topological conjugacy relation of Cantor minimal systems TopConj treated as a subset of Min(C)xMin(C) is complete analytic. In particular, TopConj is a non-Borel subset of Min(C)xMin(C). Roughly speaking, it is impossible to tell if two minimal Cantor set homeomorphisms are topologically conjugate using only a countable amount of information and computation. &lt;BR> &lt;BR> Our result is proved by applying a Foreman-Rudolph-Weiss-type construction used for an anti-classification theorem for ergodic automorphisms of the Lebesgue space. We find a continuous map F from the space of all trees over non-negative integers with arbitrarily long branches into the class of minimal homeomorphisms of the Cantor set. Furthermore, F is a reduction, which means that a tree T is ill-founded if and only if F(T) is topologically conjugate to its inverse. Since the set of ill-founded trees is a well-known example of a complete analytic set, it is impossible to classify which minimal Cantor set homeomorphisms are  topologically conjugate to their inverses. &lt;BR> &lt;BR> This is joint work with Konrad Deka, Felipe García-Ramos, Kosma Kasprzak, Philipp Kunde (all from the Jagiellonian University in Kraków). &lt;/p></div><div class="event_time">15:00 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</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">Dr. Alessandro Giacchetto (ETH Zürich)</div><div class="event_title">Resurgent large genus asymptotics of intersection numbers <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Factorials can be recursively computed through their definition, but the computation gets difficult quite quickly when the number of interest gets larger and larger. A workaround is given by Stirling’s approximation: a closed, asymptotic formula for factorials. A similar (but much more complicated) situation occurs when trying to compute Witten’s intersection numbers. Virasoro constraints recursively compute these numbers, but the computation gets difficult when the genus gets larger and larger. An approximation has been recently proved by Aggarwal by studying the structure of the associated Virasoro constraints. I will present an alternative proof of Aggarwal’s result based on quantum curves and resurgence. The advantage of this strategy is that it easily generalises to several problems (like r-spin intersection numbers, Norbury’s intersection numbers, etc) and gives higher-order corrections.</div><div class="event_time">15:00 &bull; ETH Zentrum, Building ITS, Room  </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/news-and-events/events/lecture-series/inaugural-and-farewell-lectures.html">Inaugural Lectures</a></div><br /><div class="event_speaker"><a class="external" href="https://math.ethz.ch/people/jopeters">Prof. Dr. Jonas Peters (ETH Z&uuml;rich, Switzerland)</a></div><div class="event_title">What happens if? Can we learn from data how ecosystems react to changes?</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 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. Shrawan Kumar (University of North Carolina at Chapel Hill)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Hermitian eigenvalue problem and its generalization to any semisimple group: A survey</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The classical Hermitian eigenvalue problem asks the following question: What are the possible eigenvalues of the sum A + B of two n × n Hermitian matrices A and B, provided we fix the eigenvalues of A and B. A systematic study of this problem was initiated by H. Weyl (1912). By the contributions from a long list of mathematicians, notably Weyl (1912), Horn (1962), Klyachko (1998) and Knutson-Tao (1999), the problem was finally settled. The solution asserts that the eigenvalues of A + B are given in terms of certain system of linear inequalities in the eigenvalues of A and B. These inequalities are given explicitly in terms of certain triples of Schubert classes in the singular cohomology of Grassmannians and the standard cup product. The Hermitian eigenvalue problem has been extended by Berenstein-Sjamaar (2000) and Kapovich-Leeb-Millson (2005) for any semisimple complex algebraic group G. Their solution is again in terms of linear inequalities obtained from certain triples of Schubert classes in the singular cohomology of the partial flag varieties G/P (P being a maximal parabolic subgroup) and the standard cup product. However, their solution is far from being optimal. In a joint work with P. Belkale, we have given an optimal solution of the problem for any G. We define a deformation of the cup product in the cohomology of G/P and use this new product to generate certain inequalities which optimally solves the problem for any G. The talk should be accessible to general mathematical audience.</div><div class="event_time">17:15 &bull; Universität Bern, Sidlerstrasse 5, 3012 Bern, Lecture Room B6</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, October 31      </div>      <div class="day_content">        <div class="day_content_item cancelled"><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"> Bruno Duchesne (Université Paris-Saclay)</div><div class="event_title">CANCELLED: Maximal representations and hermitian symmetric spaces of infinite dimension <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, a family of infinite dimensional Hermitian symmetric spaces will be introduced and a rigidity theorem for complex hyperbolic lattices acting by isometries on such symmetric spaces will be presented. The context of this result will be given in order to explain why one can be interested in such result.</div><div class="event_time">10:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://algebra.dmi.unibas.ch/seminar.html">Seminar Algebra and Geometry</a></div><br /><div class="event_speaker"> Christian Urech (University of Basel)</div><div class="event_title">Finitely generated subgroups of algebraic elements of plane Cremona groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let S be a variety. A birational transformation of S is called algebraic if it is contained in an algebraic subgroup of the group of birational transformations Bir(S) of S. In this talk, I will explain, why a finitely generated subgroup of Bir(S) is itself contained in an algebraic subgroup of Bir(S). This answers a question of Charles Favre. We will apply this result to describe the degree growth of finitely generated subgroups of plane Cremona groups. This is joint work with Anne Lonjou and Piotr Przytycki.</div><div class="event_time">10:30 &bull; Universität Basel, Spiegelgasse 5, Seminarraum 05.001</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/mat770.1">Oberseminar: Algebraische Geometrie</a></div><br /><div class="event_speaker">Dr. Swann Tubach (ENS Lyon)</div><div class="event_title">Higher enhancements of Nori motives and realisation functors <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let k be a field of characteristic zero and X a quasi-projective k-variety. The category of perverse Nori motives over X is an abelian category modelled on perverse sheaves but instead of having coefficients in \\Q-vector spaces, they have stalks in the Tannakian category of motives constructed by Nori. They were constructed by Ivorra and S. Morel. Their work, together with the work of Terenzi provides the 6 operations for the derived category of perverse Nori motives. By adapting an argument due to Nori in the setting of constructible sheaves on the complex points of X, we show that the derived category of perverse Nori motives is the derived category of its constructible heart. This enables us to see each of the 6 operations as a right derived functor, which have natural higher categorical lifts. Thanks to the work of Drew, Gallauer and Robalo, the existence of those lifts gives us a comparison functor from the category of Voevodsky motives over X, compatible with the operations. Our arguments also work for mixed Hodge modules, providing a Hodge realisation of étale Voevodsky motives. If times permits, we will explain how to use higher categorical tools to expand perverse Nori motives, together with the 6 operations, from quasi-projective varieties to all finite type k-schemes, and even to all qcqs schemes of characteristic zero (for those, we do not extend all the operations).</div><div class="event_time">13:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</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"> Léopold Trémant (Université de Strasbourg)</div><div class="event_title">High-order averaging and machine learning <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Highly-oscillatory phenomena combine the well-known numerical challenges of stiff equations and geometric problems, such as order reduction and energy preservation. These problems involve both fast oscillatory dynamics and slow drift dynamics, which interact to create complex dynamics. High-order averaging allows to asymptotically decouple these dynamics using formal calculations, which generates modified problems that can be solved with better numerical accuracy.In this talk, I will introduce high-order averaging using a (somewhat recent) closed form approach, and exhibit the improvement in numerical accuracy it allows. I will then present the geometric properties of the method, notably regarding the preservation of a Hamiltonian structure. The talk will end with some preliminary results regarding geometric neural networks, which can replace the offline symbolic computations of averaging with an offline training procedure.</div><div class="event_time">14:00 &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/s/daco-seminar">DACO Seminar</a></div><br /><div class="event_speaker"><a class="external" href="https://dmi.unibas.ch/de/personen/ivan-dokmanic/">Prof. Dr. Ivan Dokmani&#263; (University of Basel)</a></div><div class="event_title">Statistical Mechanics of Graph Convolution Networks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Graph neural networks (GNNs) excel in modeling relational data such as biological, social, and transportation networks, but the underpinnings of their success are elusive. Traditional complexity measures from statistical learning theory fail to account for observed phenomena like the double descent or the impact of relational semantics on generalization error. Motivated by experimental observations of ``transductive\'\' double descent in key networks and datasets, we use analytical tools from statistical physics and random matrix theory to precisely characterize generalization in simple graph convolution networks on the contextual stochastic block model. Our results illuminate the nuances of learning on homophilic versus heterophilic data and predict double descent whose existence in GNNs has been questioned by recent work. We show how risk is shaped by the interplay between the graph noise, feature noise, and the number of training labels. Our findings apply beyond stylized models, capturing qualitative trends in real-world GNNs and datasets. As a case in point, we use our analytic insights to improve performance of state-of-the-art graph convolution networks on heterophilic datasets. </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_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/seminaires/lie-sem/">Lie groups and moduli spaces </a></div><br /><div class="event_speaker"> Maxime Fairon (Orsay)</div><div class="event_title">Compatible Poisson structures on multiplicative quiver varieties <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Any multiplicative quiver variety is endowed with a Poisson structure constructed by M. Van den Bergh through reduction from a Hamiltonian quasi-Poisson structure. The smooth locus of this variety carries a corresponding symplectic form defined by D. Yamakama through quasi-Hamiltonian reduction. In this talk, I want to explain how to include this Poisson structure as part of a larger pencil of compatible Poisson structures on the multiplicative quiver variety. The pencil is defined by reduction from a pencil of (non-degenerate) Hamiltonian quasi-Poisson structures, whose construction can be adapted to various frameworks, e.g. in relation to character varieties. I will start by explaining the simpler analogous situation that leads to a pencil of Poisson structures on (additive) quiver varieties. Time allowing, I will comment on how this result can be applied to the spin Ruijsenaars-Schneider phase space; this shows the compatibility of two Poisson structures that appeared in independent works of Arutyunov-Olivucci (arXiv:1906.02619) and of Chalykh and myself (arXiv:1811.08727). </div><div class="event_time">15:15 &bull; Université de Genève, Section de mathématiques, 7-9 rue du Conseil-Général, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_fr"><a class="external" href="https://www.unifr.ch">Université de Fribourg</a></div><div class="event_type"><a class="external" href="https://commonweb.unifr.ch/_Science/Math/Pub/Math/seminars/OSgeom-top.html">Oberseminar Geometrie</a></div><br /><div class="event_speaker"> Chi Cheuks Tsang (CRM Montreal)</div><div class="event_title">Pseudo-Anosov maps, dilatations, and veering trian- gulations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A pseudo-Anosov map is a surface homeomorphism that acts with similardynamics as a hyperbolic element of SL2R on R2. A classical result ofNielsen and Thurston shows that these are surprisingly prevalent amongmapping classes of surfaces. The dilatation of a pseudo-Anosov mapis a measure of the complexity of its dynamics. It is another classicalresult that the set of dilatations among all pseudo-Anosov maps definedon a fixed surface has a minimum element. This minimum dilatationcan be thought of as the smallest amount of mixing one can performon the surface while still doing something topologically interesting. Theminimum dilatation problem asks for this minimum value.In this talk, we will present some recent progress on a version of theminimum dilatation problem concerning fully-punctured pseudo-Anosovmaps. In the first part of the talk, we will provide some backgroundof pseudo-Anosov maps and the minimum dilatation problem. In thesecond part of the talk, we will go into some technical details about oneingredient of the proof, namely, how one can obtain a bound on thenumber of tetrahedra in the layered veering triangulation associated toa fully-punctured pseudo-Anosov map with small normalized dilatation.</div><div class="event_time">15:15 &bull; Université de Fribourg, room Phys 2.52</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/mat075.1">Zurich Graduate Colloquium</a></div><br /><div class="event_speaker">Hjalti Isleifsson</div><div class="event_title">What is... higher rank hyperbolicity? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will recall the now classical notion of Gromov hyperbolicity and then discuss results due to Wenger and Kleiner-Lang on how hyperbolic phenomena arise in dimensions greater than or equal to the rank of spaces which satisfy non-positive curvature conditions.</div><div class="event_time">16:15 &bull; UZH Zentrum, Building KO2, Room F 150</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_fr"><a class="external" href="https://www.unifr.ch">Université de Fribourg</a></div><div class="event_type"><a class="external" href="https://www.unifr.ch/math/de/info/kolloquium.html">Colloquium </a></div><br /><div class="event_speaker"> Erwan Lanneau (Institut Fourier, Université Grenoble Alpes)</div><div class="event_title">Dynamics of billiard flows in polygons <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this survey talk, I will give an overview of the study of rational polygonal billiards and some of the highlights of Teichmüller dynamics. This will be the occasion to talk on infinite billiards such as the Ehrenfest model, also known as the wind-tree model.</div><div class="event_time">17:15 &bull; Université de Fribourg, room Phys 2.52</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, November 1      </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/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Dr. Johannes Schmitt (ETH Zürich)</div><div class="event_title">Log intersection theory: from toric varieties to moduli of curves III</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</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/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Peter Teichner (Max Planck Institute Bonn)</div><div class="event_title">A new extension of 4-dimensional mapping class groups</div><div class="event_time">15:45 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</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">Prof. Dr. Daniele Boffi (KAUST)</div><div class="event_title">On the numerical approximation of parameter dependent PDE eigenvalue problems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk I will discuss the numerical approximation of PDEeigenvalue problems depending on a finite number of deterministicparameters. The parameters can be part of the problem or can beintroduced by the discretization.It turns out that eigenvalue problems are influenced by the presence of parameters in a way that doesn\'t compare to the corresponding sourceproblem. We present several examples and counterexamples, showing the difficulties arising when eigenvalues and eigenfunctions need to be approximated accurately.A crucial aspect of parametric eigenvalue problems is the lack ofregularity with respect to the parameter, unless a special sorting is considered, taking into account appropriately possible crossings and clustering.On the other hand, parameters arising from the discretizing scheme can be source of spurious solutions.</div><div class="event_time">16:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room E 1.2</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/seminar-on-stochastic-processes">Seminar on Stochastic Processes</a></div><br /><div class="event_speaker">Prof. Dr. Jean Bertoin (Universität Zürich, Switzerland)</div><div class="event_title">Working group step-reinforced random walk: general presentation</div><div class="event_time">17:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room  H12</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, November 2      </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"> Javier Fresán (Sorbonne Université)</div><div class="event_title">E-functions and geometry</div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</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"> Asbjorn Nordentoft (Paris)</div><div class="event_title">Non-vanishing of finite order twists of L-values via horizontal p-adic L-functions <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Goldfeld’s Conjecture predicts that exactly 50% of quadratic twists of a fixed elliptic curve have L-function non-vanishing at the central point. Correspondingly, when considering twists by higher order Dirichlet characters, it has been predicted by David-Fearnly-Kisilevsky that 100% should be non-vanishing. Very little was previously known beyond the quadratic case as the problem lies beyond the current technology of e.g. analytic number theory. In this talk I will present a p-adic approach relying on the construction of ‘horizontal p-adic L-functions’. This yields strong quantitative non-vanishing results for general order twists. In particular, we obtain the best result towards Goldfeld\'s Conjecture for one hundred percent of elliptic curves (improving on a result of Ono). I will also present applications to simultaneous non-vanishing and Diophantine stability.This talk is based on joint work with Daniel Kriz.</div><div class="event_time">14:15 &bull; EPF Lausanne, MA A1 12</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/sfs/news-and-events/data-science-seminar">ETH-FDS seminar </a></div><br /><div class="event_speaker"> Quentin  Berthet  (Google DeepMind)</div><div class="event_title">Joint talk DACO-FDS: Perturbed Optimizers for Machine Learning <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Machine learning pipelines often rely on optimizers procedures to make discrete decisions (e.g., sorting, picking closest neighbors, or shortest paths). Although these discrete decisions are easily computed in a forward manner, they break the back-propagation of computational graphs. In order to expand the scope of learning problems that can be solved in an end-to-end fashion, we propose a systematic method to transform optimizers into operations that are differentiable and never locally constant. Our approach relies on stochastically perturbed optimizers, and can be used readily within existing solvers. Their derivatives can be evaluated efficiently, and smoothness tuned via the chosen noise amplitude. We also show how this framework can be connected to a family of losses developed in structured prediction, and give theoretical guarantees for their use in learning tasks. We demonstrate experimentally the performance of our approach on various tasks, including recent applications on protein sequences.</div><div class="event_time">16:15 &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_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"> Gady Kozma (Weizmann Institute of Science)</div><div class="event_title">Irreducibility of random polynomials  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Take a polynomial of degree n with coefficients +/-1 taken randomly, independently. What is the probability that it is irreducible over the rationals? This question is still open, but a lot of progress happened around it in recent years. We will survey some of this progress, including joint work with Lior Bary-Soroker, Dimitris Koukoulopoulos and David Hokken. </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/daco-seminar">DACO Seminar</a></div><br /><div class="event_speaker"><a class="external" href="https://q-berthet.github.io/">Dr. Quentin Berthet ( Google DeepMind)</a></div><div class="event_title">DACO-FDS: Perturbed Optimizers for Machine Learning <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Machine learning pipelines often rely on optimizers procedures to make discrete decisions (e.g., sorting, picking closest neighbors, or shortest paths). Although these discrete decisions are easily computed in a forward manner, they break the back-propagation of computational graphs. In order to expand the scope of learning problems that can be solved in an end-to-end fashion, we propose a systematic method to transform optimizers into operations that are differentiable and never locally constant. Our approach relies on stochastically perturbed optimizers, and can be used readily within existing solvers. Their derivatives can be evaluated efficiently, and smoothness tuned via the chosen noise amplitude. We also show how this framework can be connected to a family of losses developed in structured prediction, and give theoretical guarantees for their use in learning tasks. We demonstrate experimentally the performance of our approach on various tasks, including recent applications on protein sequences.</div><div class="event_time">16:15 &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_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"><a class="external" href="https://www.york.ac.uk/business-society/people/amcneil/">Prof. Dr. Alexander McNeil (University of York)</a></div><div class="event_title">Copula-based models for financial and macroeconomic time series <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We present some new approaches to modelling and forecasting macroeconomic and financial time series using stationary d-vine (s-vine) copula processes. We show how non-Gaussian extensions of ARMA processes can be constructed to model data that have non-Gaussian marginal distributions and/or non-Gaussian and non-linear serial dependence structures. We also show how these models can be combined with uniform-measure-preserving transformations known as v-transforms to construct processes for volatile financial return series which can outperform classical econometric models in certain cases. Methods will be illustrated with a variety of applications to data.</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, November 3      </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/s/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_speaker"><a class="external" href="https://math.ethz.ch/people/zerbess">Prof. Dr. Sarah Zerbes (ETH Z&uuml;rich, Switzerland)</a></div><div class="event_title">Iwasawa theory for the symmetric square of an elliptic curve <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The arithmetic of the adjoint, or symmetric square, of an elliptic curve over Q (or, more generally, of a modular form) is a particularly interesting case from the viewpoint of Iwasawa theory, not least because of its close connection with modularity-lifting problems and hence with Fermat\'s last theorem. In this talk I will describe ongoing work with David Loeffler in which we prove the cyclotomic Iwasawa main conjecture in this setting, using Euler systems for Hilbert modular surfaces.</div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</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.imsv.unibe.ch/research/talks/colloquia/index_eng.html">Colloquia on Probability and Statistics </a></div><br /><div class="event_speaker">Prof. Dr. Geir-Arne Fuglstad (NTNU Trondheim)</div><div class="event_title"><a class="external" href="https://www.imsv.unibe.ch/research/talks/colloquia/index_eng.html">Non-stationary Spatio-Temporal Modelling with Applications to Autonomous Sampling</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The ocean is dynamic and hard to sample remotely. Numerical ocean models can provide information on typical behaviour, but cannot accurately forecast local phenomena. Autonomous underwater vehicles (AUVs) can target specific areas and provide accurate measurements, but can only sample an area sparsely. We describe how to improve AUV sampling through a Gaussian process (GP) prior constructed based on the numerical ocean model, which is updated based on measurements in real-time. We consider stochastic convection-diffusion equations with different levels of complexity for spatially varying coefficients. These are fitted to numerical ocean model simulations, and constitute GP priors (or surrogate models) for the ocean behaviour. I will discuss ongoing work for modelling and estimation, and for computationally efficient updates of the priors onboard the AUVs.</div><div class="event_time">15:15 &bull; Universität Bern, IMSV, Alpeneggstrasse 22, 3012 Bern, Hörraum -203</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://www.epfl.ch/schools/sb/research/math/statistics-seminars/">Statistics Seminar </a></div><br /><div class="event_speaker"> Paul Kirk (University of Cambridge)</div><div class="event_title">Title T.B.A.</div><div class="event_time">15:15 &bull; EPF Lausanne, MA A3 31</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">Prof. Dr. Radu Laza (SUNY Stony Brook)</div><div class="event_title">Birational geometry of the moduli space of low degree K3 surfaces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />It is a question of major interest to construct meaningful compactifications for moduli spaces of algebraic varieties.  A case that proved challenging  is that of polarized K3 surfaces. I will survey the problem and the proposed solutions to it. Then, I will discus an alternative, variational approach  to it, proposed by O’Grady and I, which is particularly relevant in the case of low degree K3 surfaces. Namely, in the case of low degree K3 surfaces there are at least two natural compactifications — the Baily-Borel compactifciation and the GIT compactification. They are related by a series of simple  birational transformations “wall crossings”, that can be described explicitly. The degree 2 case is classical, going back to the 80s, the degree 4 was completed a few years ago by myself and O’Grady. Here, I report on the degree 6 case, which is work in progress with Francois Greer, Zhiyuan Li,  and Fei Si. </div><div class="event_time">16:00 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</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>';