var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-62"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-60"><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. 1</span>      <span style="float: right; text-align:right; width: 250px;">19.2 - 23.2.2024</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Spring Semester 2024</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, February 19      </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/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> Nezhla  Aghaei (SDU, U. Geneva)</div><div class="event_title">Combinatorial quantization of Chern Simons theory for gl(1|1) <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Chern-Simons theories with gauge supergroups appear naturally in string theory and they possess interesting applications in mathematics, e.g.for the construction of knot and link invariants. In this talk we explain the combinatorial quantisation of Chern-Simons theories and also the GL(1|1) generalisation of it, for punctured Riemann surfaces of arbitrary genus. We construct the algebra of observables, and study their representations and applications to the construction of 3-manifold invariants.This is based on the joint work https://arxiv.org/abs/1811.09123 and part 2 in progress with A. Gainutdinov, M. Pawelkiewicz, V Schomerus.</div><div class="event_time">13:15 &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://www.epfl.ch/schools/sb/research/math/statistics-seminars/">Statistics Seminar </a></div><br /><div class="event_speaker"> Marc Jourdan (INRIA Lille)</div><div class="event_title">Solving pure exploration problems with the Top Two approach <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In pure exploration problems for stochastic multi-armed bandits, the goal is to answer a question about a set of unknown distributions (modeling for example the efficacy of a treatment) from which we can collect samples (measure its effect), and to provide guarantees on the candidate answer. The archetypal example is the best arm identification problem, in which the agent aims at identifying the arm with the highest mean. In this talk, I will focus on the class of Top Two algorithms, which select the next arm to sample from among two candidate arms, a leader and a challenger. Due to their simplicity and interpretability, Top Two algorithms have received increased attention in recent years. In the fixed-confidence setting, Top Two algorithms have an asymptotically optimal expected sample complexity (number of collected samples when the error level vanishes). In the anytime setting, we propose a Top Two algorithm which has guarantees on the probability of misidentifying a good enough arm at any time.</div><div class="event_time">13:15 &bull; EPF Lausanne, GA 3 21</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, February 20      </div>      <div class="day_content">        <div class="day_content_item important"><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. Sam Canning (ETH Zürich)</div><div class="event_title">Non-tautological cycles on the moduli space of smooth curves <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />It is more difficult to find non-tautological algebraic cycles on moduli spaces of smooth curves than on moduli spaces of stable curves. In fact, there were only 11 known pairs (g,n) for which M_{g,n} was known to have a non-tautological algebraic cycle, due to Graber--Pandharipande and van Zelm. I will explain how to produce non-tautological algebraic cycles in infinitely many more cases. In particular, M_g has non-tautological algebraic cycles whenever g is at least 16. This is joint work with V. Arena, E. Clader, R. Haburcak, A. Li, S.C. Mok, and C. Tamborini.</div><div class="event_time">13:30 &bull; ETH Zentrum, Building ITS, 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://www.unige.ch/math/annonces/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Alexandre Heinlein (Delft University)</div><div class="event_title">Domain decomposition for physics-informed neural networks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Physics-informed neural networks (PINNs) are a class of methods forsolving differential equation-based problems using a neural network asthe discretization. They have been introduced by Raissi et al. andcombine the pioneering collocation approach for neural network functions introduced by Lagaris et al. with the incorporation of data via an additional loss term. PINNs are very versatile as they do not require an explicit mesh, allow for the solution of parameter identification problems, and are well-suited for high-dimensional problems. However, the training of a PINN model is generally not very robust and may require a lot of hyper parameter tuning. In particular, due to the so-called spectral bias, the training of PINN models is notoriously difficult when scaling up to large computational domains as well as for multiscale problems.In this talk, overlapping domain decomposition-based techniques forPINNs are being discussed. Compared with other domain decompositiontechniques for PINNs, in the finite basis physics-informed neuralnetworks (FBPINNs) approach, the coupling is done implicitly via theoverlapping regions and does not require additional loss terms. Using the classical Schwarz domain decomposition framework, a very general framework, that also allows for mult-level extensions, can beintroduced. The method outperforms classical PINNs on several types ofproblems, including multiscale problems, both in terms of accuracy and efficiency. Furthermore, the combination of the multi-level domain decomposition strategy with multifidelity stacking PINNs fortime-dependent problems will be discussed. It can be observed that the combination of multifidelity stacking PINNs with a domain decomposition in time clearly improves the reference results without a domain decomposition.</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">Dr. Eren C. Kizildag (Columbia, US)</div><div class="event_title">Computational Limits of Random Optimization Problems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Optimization problems with random objective functions are central in computer science, probability, and modern data science. Despite their ubiquity, finding efficient algorithms for solving these problems remains a major challenge. Interestingly, many random optimization problems share a common feature, dubbed as statistical-computational gap: while the optimal value can be pinpointed non-constructively, all known polynomial-time algorithms find strictly sub-optimal solutions. That is, an optimal solution can only be found through brute force search which is computationally expensive.In this talk, I will discuss an emerging theoretical framework for understanding the computational  limits of random optimization problems, based on the Overlap Gap Property (OGP). This is an intricate geometrical property that achieves sharp algorithmic lower bounds against the best known polynomial-time algorithms for a wide range of random optimization problems. I will focus on two models to demonstrate the power of the OGP framework: (a) the symmetric binary perceptron, a simple neural network classifying/storing random patterns and a random constraint satisfaction problem, widely studied in probability, statistics, and computer science, and (b) the random number partitioning problem as well as its planted counterpart, which is closely related to the design of randomized controlled trials. In addition to yielding sharp algorithmic lower bounds, our techniques also give rise to new toolkits for the study of statistical-computational gaps in other models, including the online setting.</div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1 + Zoom talk</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.unil.ch/dsa/en/home/menuinst/seminaires--evenements/research-seminars.html">Talks in Actuarial Mathematics </a></div><br /><div class="event_speaker"> Robert Stelzer (Ulm University)</div><div class="event_title">Time-varying Lévy-driven state space models, locally stationary approximations and asymptotic normality <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We first introduce time-varying Lévy-driven state space models, as a class of time series models in continuous time encompassing continuous-time autoregressive moving average processes with parameters changing over time.In order to allow for their statistical analysis we define a notion of locally stationary approximations for sequences of continuous time processes and establish laws of large numbers and central limit type results under \\theta-weak dependence assumptions. Finally, we consider the asymptotic behaviour of the empirical mean and autocovariance function of time-varying Lévy-driven state space models under appropriate conditions.This talk is based on:Bitter, A., Stelzer, R., Ströh, B. (2023):Continuous-time Locally Stationary Time Series ModelsAdvances in Applied Probability, 55 no. 3, 965 - 99Stelzer, R., Ströh, B. (2022):Asymptotics of Time-varying Processes in Continuous-Time using Locally Stationary ApproximationsarXiv:2105.00223</div><div class="event_time">16:30 &bull; EPF Lausanne, UniL campus, Extranef - 110</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, February 21      </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://ethz.ch/en/news-and-events/events/inaugural-farewell-introductory-lectures.html">Inaugural Lectures</a></div><br /><div class="event_speaker">Prof. Dr. Sarah Zerbes (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">Elliptic curves and Fermat\'s last theorem</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, February 22      </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/daco-seminar">DACO Seminar</a></div><br /><div class="event_speaker"> Sarah Timhadjelt (Aix-Marseille Université, France)</div><div class="event_title">Second largest eigenvalue of the sum of a deterministic matrix and a random permutation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We consider a random bistochastic matrix of size N of the form (1-r)M + rQ where 0&lt;r&lt;1, where M is a uniformly distributed permutation and Q is a given bistochastic matrix. We take interest in the spectral behavior for large dimension N. Under sparsity and regularity assumptions on the *-distribution of Q (that is the normalized trace of polynomials in Q and Q*), we can prove that the second largest eigenvalue of (1-r)M + rQ is essentially bounded by an approximation of the spectral radius of a deterministic asymptotic equivalent given by free probability theory. This upper-bound has application in graph theory, for instance for the construction of graph expander.</div><div class="event_time">11:15 &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/~palmeran/topsem.html">Séminaire de Topologie et Géométrie </a></div><br /><div class="event_speaker"> Ben-Michel Kohli (Yau Center, Tsinghua University)</div><div class="event_title">A lower bound for the genus of a knot using the Links-Gould invariant <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />For a long time, the Alexander polynomial was the main easily computable link invariant to be known. But in 1984, Jones discovered his well knownpolynomial link invariant, and that gave birth to the vast theory of quantum link invariants. However, unlike for the Alexander invariant, it is in general hard to deduce precise topological properties on a knot or link from the value quantuminvariants take on that link. For instance, no genus bound is known for the Jones polynomial.The Links-Gould invariants of oriented links $LG^{m,n}(L,t_{0},t_{1})$ are two variable quantum invariants obtained by the Reshetikhin-Turaev construction applied to Hopf superalgebras $U_{q}\\mathfrak{gl}(m \\vert n)$. These invariants are known to be generalizations of the Alexander invariant.Using representation theory of $U_{q}\\mathfrak{gl}(2 \\vert 1)$, we proved in recent work with Guillaume Tahar that the degree of the Links-Gould polynomial $LG^{2,1}$ provides a lower bound on the Seifert genus of any knot, therefore improving the bound known as the Seifert inequality in the case of the Alexander invariant.</div><div class="event_time">14:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Luis Paris (Université de Bourgogne)</div><div class="event_title">Geometric representations of Artin groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We are interested in the interaction between two families of groups: on the one hand, that of mapping class groups, and, on the other hand, that of simplylaced Artin groups. The \\emph{mapping class group} of a compact oriented surface, $\\Sigma$, denoted by $\\MM (\\Sigma)$, is the group of isotopy classesof homeomorphisms of $\\Sigma$ which preserve the orientation. A\\emph{simply laced Artin group} is a group defined by relations of the form $x y = y x$ and $x y x = y x y$. The aim of the talk is to explain how to construct homomorphisms from simply laced Artin groups to mapping class groups, and to explain their usefulness.</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">Dr. Salvatore Scognamiglio (Parthenope University of Naples)</div><div class="event_title">Explainable Least Square Monte Carlo for Solvency Capital Requirement Evaluation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Solvency II requires that to be solvent, insurance and reinsurance undertakings that adopt the internal model should hold their own funds able to cover losses in excess of expected ones at a given confidence level over a one-year period. This Solvency Capital Requirement (SCR) is defined as the Value-at-Risk of the Net Asset Value probability distribution at a 99.5% confidence level over a one-year period. Estimating the SCR involves nested simulations, incurring prohibitive computational costs. While machine and deep learning methods exhibit accuracy, their lack of explainability impedes adoption in the highly regulated insurance sector. This paper introduces an extension of the Least Square Monte Carlo method based on recent advances in explainable deep learning known as ‘localGLMnet’. The proposed approach allows for an accurate estimation of the SCR without compromising model explainability. It allows for deriving some interesting insights into the impact of risk factors on the value of the insurance liabilities. Numerical experiments performed on two realistic insurance portfolios validate our proposal. Additionally, we illustrate that the ElasticNet regularisation can be applied to enhance the model’s performance further.</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, February 23      </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://www.epfl.ch/schools/sb/research/math/statistics-seminars/">Statistics Seminar </a></div><br /><div class="event_speaker"> Cyril  Letrouit  (CNRS & U. Paris-Saclay)</div><div class="event_title">Two mathematical perspectives on transformers <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will present joint works with Borjan Geshkovski Yury Polyanskiy and Philippe Rigollet in which we use tools from ODEs and PDEs to study an interacting particle system arising in Transformers through a mechanism called ``self-attention”. We demonstrate the formation of clusters of particles as time goes to infinity. I will also report on a joint work with Andrei Agrachev in which we use tools from geometric control theory to understand universal approximation properties of these particle systems.</div><div class="event_time">13:15 &bull; EPF Lausanne, GA 3 21</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/labs/anmath/seminars/">Seminar of Analysis </a></div><br /><div class="event_speaker"> Julien Royer</div><div class="event_title">Local energy decay and low frequency asymptotics for the Schrödinger equation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We are interested in the local energy decay for the Schrödinger equation in an asymptotically Euclidean setting. For this, we study in particular the behavior of the corresponding resolvent for low frequencies. We will see how to use some ideas coming from the analysis of the damped wave equation to get the asymptotic profile for the resolvent, and then for the large time behavior of the solution.</div><div class="event_time">14:15 &bull; EPF Lausanne, MA B1 11</div>        </div>        <div class="day_content_item cancelled"><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">Dr. Francesco Lemma (Université Paris Cité)</div><div class="event_title">CANCELLED: Kato explicit reciprocity law for Siegel modular forms of weight 3,3 <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In a series of papers, Loeffler-Zerbes and their collaborators constructed a non-zero Euler system for Siegel modular forms, providing the first evidence for the BSD conjecture for abelian surfaces of rank 0. I will present a proof of the non-triviality of the Euler system for the minimal cohomological weight by the generalized explicit reciprocity law for the critical twist, following Kato. This is a joint work with Tadashi Ochiai (Tokyo Institute of Technology).</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_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. Sheldon Katz (Univ. of Illinois and FIM)</div><div class="event_title">The generating function of Euler characteristics of Hilbert schemes of points on a supermanifold <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 extend well-known results on the generating function of Euler characteristics of Hilbert schemes of points from complex manifolds to complex supermanifolds.  These are two-variable generating functions in general: since functions on a zero dimensional subscheme of a supermanifold are Z_2-graded, there is an even degree and an odd degree.  For supermanifolds of a given superdimension (n|m), the generating function can be expressed in terms of the corresponding generating function for C^{n|m}, which can in turn be computed by an analogue of box-counting.   These basic generating functions are worked in low superdimension and can be expressed as rational functions of two variables.</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>';