var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-33"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-31"><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. 13</span>      <span style="float: right; text-align:right; width: 250px;">12.5 - 16.5.2025</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Spring Semester 2025</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, May 12      </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/events/">Seminar in Mathematics </a></div><br /><div class="event_speaker"> Yuval  Wigderson</div><div class="event_title">The approximate structure of triangle-free graphs <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A natural way of constructing a dense triangle-free graph is to start with a triangle-free graph $G_0$ of bounded size, blow it up, and then delete some edges. Many of the natural triangle-free graphs we encounter, such as all bipartite graphs, can be obtained in this way.Astonishingly, deep results in extremal graph theory imply that this is essentially the *only* way of constructing dense triangle-free graphs (up to a small error). Unfortunately, such results are of limited applicability, due to the poor quantitative aspects of known proof techniques. In this talk, I will discuss this problem, and describe several settings in which we can prove much stronger bounds. No background in extremal graph theory will be assumed.Based on joint work with Lior Gishboliner and Eoin Hurley.</div><div class="event_time">14:30 &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/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Filip Bro&#263;i&#263; (Universität Augsburg, Germany)</div><div class="event_title">Riemannian distance and symplectic embeddings in cotangent bundles <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the talk, I will introduce a distance-like function on the zero section of the cotangent bundle using symplectic embeddings of standard balls inside an open neighborhood of the zero section. I will provide some examples which illustrate the properties of such a function. The main result that I will present is a relationship between the length structure associated to the introduced quantity and the usual Riemannian length. This relationship requires upper bound coming from the existence of a J-holomorphic curve, and lower bound coming from an explicit construction which is related to the strong Viterbo conjecture. Time permitting, I will mention two different flavors of the Gromov width that are contained in joint works with Dylan Cant.</div><div class="event_time">15:15 &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_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/mpseminar/seminar.html">Séminaire de Mathématique Physique </a></div><br /><div class="event_speaker"> Philip Easo (Caltech)</div><div class="event_title">Locality of the critical point for percolation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> I will sketch why the critical point for percolation on an infinite transitive graph G only depends on the geometry of G on small scales (except in the degenerate case when G is one-dimensional). This is based on joint work with Hutchcroft (https://arxiv.org/abs/2310.10983) and was predicted by Schramm around 2008. Our techniques are inspired by a lot of previous progress on the problem, most significantly by recent work of Contreras, Martineau, and Tassion, who handled the case of graphs with polynomial growth in 2022. Our proof uses random walks and the geometry of nilpotent groups in the service of percolation arguments.</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/sfs/news-and-events/stiefel-lectures">ETH-FDS Stiefel Lectures</a></div><br /><div class="event_speaker"> Andrew Stuart (Caltech)</div><div class="event_title">Allowing Image And Text Data To Communicate  (Attention Is Sometimes Useful) <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A fundamental problem in artificial intelligenceis the question of how to simultaneously deploy data from different sources such as audio, image, text and video; such data is known as multimodal. In this talk I will focus on the canonical problem of aligning image and text data, and describe some of the mathematical ideas underlying the challenge of allowing them to communicate. I will describe the encoding of text and image in Euclidean spaces and describe contrastive learning methodology to identify and learn embeddings which align these two modalities. In so doing I will then describe the attention mechanism, a form of nonlinear transform that quantifies correlation in vector-valued sequences. Attention turns out to be useful beyond this specific context, and I will show how it may be used to design and learn maps between Banach spaces or between metric spaces of probability measures. The former is useful for accelerating MCMC, and the latter for nonlinear filtering.</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. Rafael Andrist (University of Ljubljana)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Holomorphic automorphisms of Markov surfaces</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Diophantine solutions of the equation x² + y² + z² = 3xyz were originally considered by Markov and are now called Markov triples. Later, this equation was studied over the complex numbers by algebraic geometers; The group of algebraic automorphisms is discrete and acts transitively on the Markov triples. We describe the identity component of the group of volume-preserving holomorphic automorphisms. In contrast to the algebraic case, this group is infinite-dimensional and interpolates any permutation of (ordered) Markov triples. The results can be extended to so-called Markov surfaces ofthe form x² + y² + z² &#8722; 3xyz &#8722; Ax &#8722; By &#8722; Cz &#8722; D = 0.</div><div class="event_time">17:15 &bull; Universität Bern, Sidlerstrasse 5, 3012 Bern, Room B6</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, May 13      </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/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Ilya  Pavlyukevich (Friedrich Schiller University Jena, Germany)</div><div class="event_title">A Tail-Respecting Explicit Numerical Scheme for Lévy-Driven SDEs With Superlinear Drifts <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We present an explicit numerical approximation scheme for the effective simulation of solutions to a multivariate stochastic differentialequation (SDE) with a superlinearly growing dissipative drift, driven by a multiplicative heavy-tailed Lévy process. The scheme combines the well-known Euler method with a Lie-Trotter-type splitting technique. The specific ordering of the splitting terms enables the approximation to capture all finite moments of the true solution. In the special case of SDEs driven solely by Brownian motion, our numerical scheme preserves the solution\'s superexponential moments. We prove strong convergence of approximations and determine the order of convergence.This talk is based on the joint work with O. Aryasova (Jena) and O.Kulyk (Wroclaw), arXiv:2504.07255 [math.PR]</div><div class="event_time">10:30 &bull; Université de Genève, Conseil Général 7-9, Room 6-11</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/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Dario  Ascari (University of the Basque Country)</div><div class="event_title">The Dehn function of subgroups of direct products of free groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Subgroups of direct products of free groups can be very wild in general; however, they become much more controlled once they are required to satisfy some finiteness condition. We investigate the Dehn function of such groups, an isoperimetric inequality which describes the complexity of solving the word problem. We show that, for subgroups of type F_{n-1} in a product of n factors, there is a uniform polynomial bound of N^9 on all the Dehn functions. We also show an example of a subgroup whose Dehn function is exactly N^4; the computation is based on an invariant built using braid groups.</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://dmi.unibas.ch/de/forschung/mathematik/algebraische-geometrie/">Seminar Algebra and Geometry</a></div><br /><div class="event_speaker"> Pascal Fong (Leibniz Universität Hannover)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-pascal-fong-leibniz-universitaet-hannover/">Isotrivial elliptic surfaces</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Recently, Brion introduced and developed the theory of equivariantly normal curves. These curves arise naturally in the study of smooth projective surfaces equipped with a faithful action of an elliptic curve. We will see that such a surface is isomorphic to a contracted product E\\times^G X, where E is an elliptic curve, G is a finite subgroup scheme of E and X is a G-normal curve. In this talk, we study this family of surfaces, which contains the classical example of quasi-hyperelliptic surfaces given by Bombieri and Mumford.</div><div class="event_time">10:30 &bull; Universität Basel, Seminarraum 00.003, Spiegelgasse 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/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Dr. Alexis Michelat (EPFL )</div><div class="event_title">Morse Index Stability of Branched Willmore Immersions <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We show the upper semi-continuity of the sum of the Morse index and nullity of Willmore immersions of bounded energy. In previous work in collaboration with Tristan Rivière, we had established the result under the assumption that the bubbles appearing in the limit are free of branch points, and in this talk, we will explain how to generalise this result if branch points arise. This will lead us to study fine properties of two families of 4th order elliptic operators with regular singularities.</div><div class="event_time">15:15 &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://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">Luca Rubio (ETH)</div><div class="event_title">What is... the distribution of p-tower groups? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The p-tower group of an imaginary quadratic number field K is the Galois group over K of the maximal unramified pro-p extension of K. It is known that the abelianization of the p-tower group is naturally isomorphic to the p-primary part of the narrow ideal class group Cl_K[p]. The Cohen-Lenstra heuristics give a probabilistic explanation for how often Cl_K[p] is isomorphic to a given finite abelian p-group. The goal of this talk is to generalise the Cohen-Lenstra heuristics to the non-abelian case.</div><div class="event_time">16:30 &bull; UZH Zentrum, Building KO2, Room F 150</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/la-une/maths-partag-2024">Maths à PartaG</a></div><br /><div class="event_speaker"> Jean-Baptiste  Aubin  (Université de Lyon)</div><div class="event_title">Comment être élu à tous Les coups? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Et si, grâce aux mathématiques, nous repensions la façon même dont nous votons ? Enjeu capital et constitutif des démocraties représentatives, l’élection (et le mode de scrutin associé) est l’outil d’expression incontournable des citoyennes et des citoyens. Etudier les modes de scrutin d\'un point de vue mathématique permet de dégager des conditions importantes à respecter. Cependant, un théorème important établi par l\'économiste américain K. Arrow (Prix Nobel d\'économie 1972) a laissé penser qu\'il était impossible de trouver un mode de scrutin mathématiquement satisfaisant. Aujourd’hui, de nouvelles approches, basées sur l’évaluation plutôt que sur le classement, permettent d’envisager le vote autrement. Venez les découvrir !</div><div class="event_time">18:30 &bull; Université de Genève, Uni Dufour, U300</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, May 14      </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"> Adam Kanigowski (University of Maryland)</div><div class="event_title">Sparse Equidistribution Problems in Dynamics</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"> Shivang  Jindal</div><div class="event_title">Quantum groups from cohomological Donaldson-Thomas theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In 2010, Kontsevich and Soibelman defined Cohomological Hall Algebras for quivers and potential as a mathematical construction of the algebra of BPS states. These algebras are modeled on the cohomology of vanishing cycles, which makes these algebras particularly hard to study but often result in interesting algebraic structures. A deformation of a particular case of them gives rise to a positive half of Maulik-Okounkov Yangians. The goal of my talk is to give an introduction to these ideas and explain how for the case of tripled cyclic quiver with canonical cubic potential, this algebra turns out to be one-half of the universal enveloping algebra of the Lie algebra of matrix differential operators on the torus, while its deformation turn out be one half of an explicit integral form of the Affine Yangian of gl(n). Time permitting, we will see how these ideas can be fermionzed and used to study the case of resolved conifold.</div><div class="event_time">13:00 &bull; EPF Lausanne, CE 1 100</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://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Prof. Dr. Caroline Series (University of Warwick)</div><div class="event_title">Convergence of spherical averages for Fuchsian groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Given a measure preserving action of a group G on a probability space X and a real valued function f on X, we consider the spherical averages S_n(f) of the functions f(g.x) averaged over all elements g of length n in a fixed set of generators. The limiting behaviour of S_n(f) has long been studied. Cesaro convergence  has been proved in a wide variety of contexts. Actual convergence  (depending on the parity of n) for free groups was proved by Nevo-Stein  for f in L^p, p&gt;1 In 2002, Bufetov extended the Nevo-Stein result to a slightly wider class by using a certain self-adjointness property of an associated Markov operator, which in turn depends on the fact that the inverse of a reduced word in a free group is itself reduced. In this talk we explain the same result for a large class of Fuchsian groups with presentations whose relations all have even length. The method relies on a new twist on the Bowen-Series coding for Fuchsian groups: by encoding the set of all shortest words representing a particular group element simultaneously, we obtain a suitable self-adjointness property of an associated Markov operator to which we apply a variant of Bufetov&#039;s original proof. This is joint work with Alexander Bufetov and Alexey Klimenko.  [Published in Comm Math Helv 2023]</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room F 5</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://dmi.unibas.ch/de/forschung/mathematik/analysis/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker"> Stefan Skondric (FAU Erlangen)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-stefan-skondric-fau-erlangen/">Existence and uniqueness of Leray-Hopf weak solution for the inhomogeneous 2D Navier--Stokes equations without vacuum</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We prove the existence and uniqueness of weak solutions of the inhomogeneous incompressible Navier--Stokes equations without vacuum using the relative energy method. We present a novel and direct proof of the existence of weak solutions based on approximation with more regular solutions. The analysis we employ to justify the strong convergence reveals how to conclude the stability and uniqueness of weak solutions.</div><div class="event_time">14:15 &bull; Universität Basel, Spiegelgasse 5, Seminarraum 05.002</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://dmi.unibas.ch/de/forschung/mathematik/algebraische-geometrie/">Seminar Algebra and Geometry</a></div><br /><div class="event_speaker"> Sokratis Zikas (IMPA)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-sokratis-zikas-impa/">On Mori Dreamness of blowups along space curves</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Mori Dream Spaces are a special kind of varieties introduced by Hu and Keel that enjoy very good properties with respect to the Minimal Model Program. While Mori Dreamness is a very desirable property, it is not very well behaved with respect to even the simplest birational maps: blowups. In this talk we study Mori Dreamness of blowups along space curves: we provide various sufficient criteria as well obstructions to the blowup being a Mori Dream Space. We also study how this property behaves while varying the curve in the corresponding Hilbert scheme and show that it is neither an open nor a closed condition. Furthermore we exhibit examples of Hilbert schemes whose general element does not give rise to a Mori Dream Space, while special elements do, and vice versa. This is joint work in progress with Tiago Duarte Guerreiro.</div><div class="event_time">14:30 &bull; Universität Basel, Seminarraum 00.003, Spiegelgasse 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.epfl.ch/schools/sb/research/math/de-rham/">Journée Georges de Rham </a></div><br /><div class="event_speaker"> Ronald  Coifman (Yale University)</div><div class="event_title">MATHEMATICAL ORCHESTRATIONS: Revealing and encoding hidden structures in empirical data (sensory or data streams) <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Our goal is to explain a methodology for sorting, organizing and assembling garbled data ,. Think of of an orchestra recording, which needs to be decomposed into the scores of the various instruments Or more the more challenging task of modeling a recording of neuronal fluctuations that needs to be separated into the scores of different activity units. . We will demonstrate and explain a few organizational methods to sort and unscramble data ,derive latent dynamic variables, and build a data derived optimized structural vocabulary analogous to a musical score.</div><div class="event_time">15:00 &bull; Université de Genève, Room U300, Uni Dufour.</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"> Stefanie Zbinden (Heriot-Watt University)</div><div class="event_title">The contraction space and its applications <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the realm of CAT(0) groups, there exists the following powerful dichotomy. Either the group has linear divergence, in which case all asymptotic cones are cut-point free, or the group has a Morse geodesic, in which case all asymptotic cones have cut-points and the group is acylindrically hyperbolic. This talk focuses on work in progress with Cornelia Drutu and Davide Spriano, where we show that the above dichotomy holds for a larger class of groups. In particular, that it holds for groups acting \'\'nicely\'\' on injective metric spaces and geodesic median spaces. The main tool of the proof is the contraction space construction, a construction which assigns a hyperbolic space to any given geodesic metric space. We will introduce and motivate this construction and outline how it can be used in the proof of the dichotomy.</div><div class="event_time">15:30 &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_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/schools/sb/research/math/de-rham/">Journée Georges de Rham </a></div><br /><div class="event_speaker"> Terrence Sejnowski  (Salk Institute & UC San Diego)</div><div class="event_title">BRAINS AND AI <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The introduction of ChatGPT in 2023 was a watershed moment for brain-inspired AI. It was as if a space alien suddenly appeared that could communicate with us eerily humanly, talking with us in perfectly formed English sentences. Only one thing is clear—ChatGPT is not human, even though LLMs are already superhuman in their ability to extract information from the world’s vast database of text. We are on an adventure that is taking us to terra incognita. This lecture will explore the origins of modern AI and the many questions that it has raised: Does ChatGPT truly understand what it is saying? Why does ChatGPT hallucinate? What impact will ChatGPT and its successors have on jobs? Should we be worried that AI may someday become superintelligent?</div><div class="event_time">16:20 &bull; Université de Genève, Room U300, Uni Dufour.</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. Michael Feischl (TU Wien)</div><div class="event_title">Optimal convergence rates in the context of neural networks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We present two recent results on the convergence rates of algorithms involving neural networks:First, we propose a hierarchical training algorithm for standard feed-forward neural networks that adaptively extends the network architecture as soon as the optimization reaches a stationary point. By solving small (low-dimensional) optimization problems, the extended network provably escapes any local minimum or stationary point. Under some assumptions on the approximability of the data with stable neural networks, we show that the algorithm achieves an optimal convergence rate s in the sense that loss is bounded by the number of parameters to the -s. Second, we show that quadrature with neural network integrands is inherently hard and that no higher-order algorithms can exist, even if the algorithm has access to the weights of the network.</div><div class="event_time">16:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</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/news-and-events/events/lecture-series/inaugural-introductory-farewell-lectures.html">Farewell Lectures</a></div><br /><div class="event_speaker">Prof. em. Dr. Marc Burger (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">CANCELLED: Spaces of Geometric Structures</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 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/seminar-on-stochastic-processes">Seminar on Stochastic Processes</a></div><br /><div class="event_speaker">Prof. em. Dr. Marc Burger (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">CANCELLED: Farewell Lecture Prof. Marc Burger</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, May 15      </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://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"> Andreas Hayash</div><div class="event_title">Symmetries of geometric Eisenstein series <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will report on work in progress, joint with Justin Campbell. For a reductive group G,we prove a factorizable Koszul duality result for the spherical category associated to the affineGrassmannian of G. As a consequence, we construct an action of the Langlands dual Lie algebra&#487; on the intersection cohomology of the moduli of quasimaps from a curve X into the flag varietyG/B, similar to one introduced by Feigin, Finkelberg, Kuznetsov, and Mirkovíc. Along the waywe develop some infinite-dimensional deformation theory using techniques inspired by recentwork of Clausen and Scholze on “solid” geometry.</div><div class="event_time">10:15 &bull; EPF Lausanne, MA A1 12</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"> Tommaso Pedroni</div><div class="event_title">Classical conformal blocks, blow-up equations and periodic spectral 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, we will examine the correspondences between 4d N=2 supersymmetric gauge theories, 2d conformal field theory and quantum integrable systems.In particular, we will address the difficulties in applying the Nekrasov-Shatashvili (NS) quantization scheme to quantum integrable systems with periodic potentials, focusing on the simplest elliptic case.Starting from two-point torus conformal blocks with a degenerate insertion, I will analyze their monodromy properties and show how the classical limit of the BPZ equation leads to the Lamé equation and its connection formulas.I will then examine the analytic structure of classical conformal blocks, showing how apparent poles become branch points through a partial resummation obtained by solving a specific limit of the C^{2}/Z_{2} blow-up equations.Finally, we will study the periodic spectral problems associated with the Lamé equation using this newly acquired information about classical conformal blocks. </div><div class="event_time">13:00 &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://www.eth-its.ethz.ch/activities/its-science-colloquium.html">ITS Science Colloquium</a></div><br /><div class="event_speaker"> Peter Bühlmann (ETH Zürich)</div><div class="event_title"><a class="external" href="https://eth-its.ethz.ch/activities/its-science-colloquium.html">Perturbation Data Science</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />\'Perturbation Data Science\' refers to the development of data science methods and algorithms that leverage the effects of perturbations -- often unspecific -- within data. We will focus on a key aspect of this framework, exploring the links between invariance learning, robustness, and causality. We will highlight how these concepts have been applied to medical and public health problems, and we will emphasize the importance of validating machine learning and AI algorithms on perturbations that occur in real-world problems.</div><div class="event_time">16:00 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room E 3</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"> Geoffrey Grimmett (University of Cambridge        )</div><div class="event_title">Democratic representation theory for the mathematician <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Mathematics illuminates democracy in a variety of ways, and the speaker will share his experiences in three areas. Firstly, the introduction of stochastics into apportionment systems. Secondly, the apportionment of the seats of the European Parliament between member states (in theory and practice). Thirdly, some mathematical aspects of voting in two-tier systems such as the EU Council. There are slight connections to percolation and the Ising model.</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://k-os.math.ethz.ch">[K-OS] Knot Online Seminar</a></div><br /><div class="event_speaker"> Jingyin Huang (Ohio State University)</div><div class="event_title">Exotic aspherical 4-manifolds</div><div class="event_time">16:15 &bull; <a class="external" href="https://u-paris.zoom.us/j/87853056962">online</a></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/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Dr. Asbjørn Bækgaard Lauritsen (Paris Dauphine)</div><div class="event_title">Energies of dilute Fermi gases <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Recently much interest has been given to the study of dilute interacting Bose and Fermi gases. For both the Bose gas and Fermi gas with spin the ground state energy densities differ to leading order from that of the free (non-interacting) gases by a term of order $a_s \\rho^{2}$ with $a_s$ the $s$-wave scattering length of the repulsive interaction. In contrast, for a spin-polarized Fermi gas, the difference is instead of order $a_p \\rho^{8/3}$ with $a_p$ the $p$-wave scattering length. I will discuss some intuition behind these results and in particular how the $p$-wave term is related to the Pauli exclusion principle. Joint work with Robert Seiringer.</div><div class="event_time">16:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 46</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. David Criens  (University of Freiburg)</div><div class="event_title">On convex expectations, penalty functions and convex semigroups on path space <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk we discuss three objects from different areas of mathematics: convex expectations from probability theory, penalty functions from stochastic optimal control and convex semigroups from analysis. In a path space setting, we explain that they have a one-to-one relation. Further, we discuss two important consequences of these relations. First, we show that convex expectations on path space are determined by their finite dimensional distributions. As a consequence, we may relate Hu and Peng’s axiomatic definition of \\(G\\)-Levy processes to the control description of Neufeld and Nutz. Second, refining this result further, we show that convex expectations with a certain Markovian structure are determined by convex semigroups on the state space. In case time allows, we discuss an application of this result, namely that certain sublinear expectations on path space are characterized uniquely by their infinitesimal structure on the state space and that they admit a stochastic control representation. This talk is based on joint work with Michael Kupper (University of Konstanz): arXiv:2503.10572</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, May 16      </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"> Boris Bukh (Carnegie Mellon University)</div><div class="event_title">Discrete 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_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://stat.ethz.ch/events/zukost">ZueKoSt: Seminar on Applied Statistics</a></div><br /><div class="event_speaker"> Stephan Mandt (University of California, Irvine)</div><div class="event_title">Scientific Inference with Diffusion Generative Models <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Diffusion models have transformed generative modeling in various domains such as vision and language. But can they serve as tools for scientific inference? In this talk, I present a perspective that reframes diffusion models as Bayesian solvers for scientific inverse problems—involving a noisy measurement process--with applications ranging from climate modeling to astrophysical imaging. Scientific use cases demand more than photorealism—they require calibrated uncertainty, distributional fidelity, efficient conditional sampling, and the ability to model heavy-tailed data. I’ll highlight four recent advances developed to meet these needs:1.  Variational Control, an improved framework for conditional generation in pretrained diffusion models (ICML ’25)  2.  Heavy-Tailed Diffusion Models, for enabling accurate modeling of sparse and extreme-valued scientific data (ICLR ’25)  3.  Conjugate Integrators, for enabling fast conditional sampling without retraining (NeurIPS  ’24)  4.  Generative Uncertainty for Diffusion Models, for assessing and exploiting epistemic uncertainties in data generation tasks (UAI \'25) Speaker: Prof. Stephan Mandt [He is an Associate Professor of Computer Science and Statistics at the University of California, Irvine. His research contributes to the foundations and applications of generative AI, with a focus on generative modeling of 2D, 3D, and sequential data, compression, resource-efficient learning, inference algorithms, and AI-driven scientific discovery. He is a Chan Zuckerberg Investigator and AI Resident and has received the NSF CAREER Award, the UCI ICS Mid-Career Excellence in Research Award, and a Kavli Fellowship. Before UCI, he led the machine learning group at Disney Research and held postdoctoral positions at Princeton and Columbia. Stephan frequently serves as a Senior Area Chair for NeurIPS, ICML, and ICLR and was most recently Program Chair for AISTATS 2024 and General Chair for AISTATS 2025.] </div><div class="event_time">15:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room E 33.5</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"> Gil  Kur (ETH Zurich)</div><div class="event_title">Title T.B.A.</div><div class="event_time">15:15 &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/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Dr. Henry  Liu (Kavli IPMU (Tokyo))</div><div class="event_title">Wall-crossing in cohomology, K-theory, and beyond <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will explain master space techniques for performingwall-crossing in moduli of sheaves on surfaces and similar spaces. Forinstance, such techniques can be used to give a topological criterion for the invariance of (equivariant) elliptic genus in variation of GIT. Joyce recently discovered that the resulting wall-crossing formulas, in (co)homology, are controlled by a vertex algebra. This result may be lifted to equivariant K-theory, and, in joint work with Nikolas Kuhn and Felix Thimm, to moduli of sheaves on Calabi-Yau 3-folds and similar spaces. The key technique is a "symmetrized pullback" operation for symmetric obstruction theories. An immediate application is an explicit Donaldson-Thomas/Pandharipande-Thomas correspondence for descendent vertices.</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>';