var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-18"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-16"><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;">30.3 - 3.4.2026</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Spring Semester 2026</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, March 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://math.ethz.ch/s/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> A. Cabrera</div><div class="event_title">Associative half-densities and quantization <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, the idea is to first motivate the appearance of half-densities along the graph of a symplectic groupoid multiplication as a semiclassical approximation to a star product. Then, we introduce the corresponding associativity axiom and present an existence and classification result for such structures. Finally, we apply this theory to understand structurally the "1-loop factor" in Kontsevich\'s star product for a coordinate Poisson manifold. We also discuss in detail the case of a linear Poisson structure in which "Duflo factors" appear naturally as an underlying canonical half-density. This is based on joint work with G. Ledesma.</div><div class="event_time">13:30 &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/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Marco   Mazzucchelli (Sorbonne Université (IMJ-PRG))</div><div class="event_title">Closed geodesics and the first Betti numbers <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, based on joint work with Gonzalo Contreras, I will sketch a proof of the following theorem: on any closed manifold of dimension at least two with non-zero first Betti number, a C<sup>&#8734;</sup> generic Riemannian metric has infinitely many closed geodesics, and indeed closed geodesics of arbitrarily large length. I will derive this result as a consequence of the following new theorem of independent interest: the existence of minimal closed geodesics, in the sense of Aubry-Mather theory, implies the existence of a transverse homoclinic, and thus of a horseshoe, for the geodesic flow of a suitable C<sup>&#8734;</sup>-close Riemannian metric.</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"> Herbert Spohn</div><div class="event_title">Generalized hydrodynamics and random matrix theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Lax matrices are a key tool in the study of integrable classical many-particle systems.If the initial conditions for the dynamical evolution are random, then the Lax matrix will be random.Because of integrability these random matrices have a very particular structure. In my presentation,I will explain the connection to generalized hydrodynamics. But the focus will beon random matrices, their density of states, and eigenvectors.</div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, March 31      </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/mat770.1">Oberseminar: Algebraische Geometrie</a></div><br /><div class="event_speaker">Beat Zurbuchen (ETHZ)</div><div class="event_title">Spreading out perverse sheaves and Kashiwara&#039;s conjectures <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>Kashiwara&apos;s conjectures are deep statements about the cohomology of semisimple perverse sheaves, including the decomposition theorem and the Hard Lefschetz theorem. I will describe a new specialization method for perverse sheaves, which allows one to extend geometrically irreducible perverse sheaves from the generic fiber to a relatively perverse sheaf over an arbitrary quasi-excellent base scheme. This specialization method implies Kashiwara&apos;s conjectures for arithmetic complexes and implies stronger semisimplicity statements than were available before. The goal of this talk is to describe the extension theorem and its applications. This is work in progress.&lt;/p></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"> Pierre-Henri  Cocquet</div><div class="event_title">Schémas numériques avec correction de dispersion pour des problèmes de propagation d\'ondes  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />L\'approximation numérique de problèmes de propagation d\'onde souffre de l\'erreur de dispersion.Cette dernière provient d\'une différence entre les vitesses de phase associées aux ondes des problèmes continu etdiscret. Elle implique de considérer des maillages très fins pour pouvoir être correctement prise en compte et ainsiobtenir des solutions numériques avec une précision fine.Dans ce séminaire, on commencera par présenter une technique de correction de dispersion pour l\'équation de Helmholtzdiscrétisée par différences finies. Cette méthode est basée sur l\'introduction d\'une perturbation du nombre d\'onde dansle schéma et permet notamment de réduire l\'erreur relative pour des maillages suffisamment fins.On montrera ensuite comment cette technique peut être étendue pour l\'équation des ondes temporelle.Enfin, on illustrera les effets de chaque méthode de correction proposée au travers d\'expériences numériques.</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_dis"><a class="external" href="https://unidistance.ch">UniDistance Suisse</a></div><div class="event_type"><a class="external" href="https://unidistance.ch/en/mathematiques-et-informatique/recherche/number-theory/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_speaker"> Ignacio  Muñoz Jiménez  (University of Genova)</div><div class="event_title">Gross points in ordinary families of Hilbert modular forms <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />he Gross--Zagier formula provides a fundamental link between central derivatives of L-functions and Heegner points on indefinite Shimura curves. In this talk, I will focus on the other side of the picture: the arithmetic of definite quaternion algebras and definite Shimura varieties. In this setting, I will explain how Gross points, the counterpart of Heegner points, can be used to construct an anticyclotomic p-adic L-function. I will then discuss how this construction interpolates in Hida families of modular forms, and I will conclude with a review of recent work extending these ideas to the totally real setting.</div><div class="event_time">15:00 &bull; <a class="external" href="https://tinyurl.com/UniDistanceNTSeminar">UniDistance Suisse, Zoom</a></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">Prof. Dr. Patricia  Alonso Ruiz (Friedrich Schiller University Jena)</div><div class="event_title">Trying to solve cubic NLS on a fractal? Maybe not by fixed point if you start below Sobolev... <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Duhamel and the fixed point theorem are often your best allies when solving non-linear PDEs like the cubic non-linear Schrödinger equation (NLS). This PDE has its origins in quantum mechanics, and it plays a prominent role in the modeling of dispersive wave phenomena, as for instance Bose-Einstein condensation.Dispersion is affected by the nature of the underlying geometry of the space it evolves, and in this talk we will address the basic question: Can one solve the cubic NLS modeling dispersion on the Sierpinski gasket? The latter is a common prototype of a compact fractal set.To approach the problem, we will call our allies Duhamel and the fixed point theorem. With a mixture of surprise (?) and perplexity (?) we will realize they are of no help to prove existence of solutions when the initial data has regularity below the threshold for the Sobolev embedding. What a different picture than in the torus or the sphere! Afterwards, if time permits, we will connect this result to (the absence of) Strichartz estimates. In any case, excitement will fill the stage :)Results are part of joint work with Gigliola Staffilani (MIT).</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://math.ethz.ch/s/zurich-colloquium-in-mathematics">Zurich Colloquium in Mathematics</a></div><br /><div class="event_speaker"> Hendrik Lenstra (Leiden University)</div><div class="event_title">Polynomial-time algorithms in algebraic number theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This lecture requires no previous knowledge of algebraic number theory, as even the most elementary notions of that theory are computationally too complicated to be accessible by algorithms that run in polynomial time. Thus, the field described by the title is quite restricted in scope. The best results were obtained by means of a relatively recently developed technique that is closely related to the method of "blowing up" known from algebraic geometry. It is hoped that the latter field will also profit from the insights gained by the new algorithmic approach.The lecture represents joint work with Daan van Gent and Alexander Spieksma.</div><div class="event_time">16:30 &bull; UZH Zentrum, Building KO2, Room F 150</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, April 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://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Elias Dubno (Universität Zürich)</div><div class="event_title">Winding of low-lying closed geodesics <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>The winding statistics of closed geodesics on the modular surface depend strongly on how one samples the geodesics: allowing deep excursions into the cusp yields heavy-tailed Cauchy laws, whereas suppressing these excursions produces Gaussian limits. I will explain this transition using continued fraction expansions and the associated digit sums, and discuss results for low-lying geodesics, where geometric length and symbolic length become comparable.&lt;/p></div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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/stoan/probability-stochastic-analysis-seminar/">Probability (and Stochastic Analysis) Seminar </a></div><br /><div class="event_speaker"> Antti  Knowles  (Geneva)</div><div class="event_title">Random graphs as models of quantum disorder <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A disordered quantum system is mathematically described by a large Hermitian random matrix. One of the most remarkable phenomena expected to occur in such systems is a localization-delocalization transition for the eigenvectors. Originally proposed in the 1950s to model conduction in semiconductors with random impurities, the phenomenon is now recognized as a general feature of wave transport in disordered media, and is one of the most influential ideas in modern condensed matter physics. A simple and natural model of such a system is given by the adjacency matrix of a random graph. I report on recent progress in analysing the phase diagram for the Erdös-Renyi model of random graphs. In particular, I explain the emergence of fully localized and fully delocalized phases, which are separated by a mobility edge. I also explain how to obtain optimal delocalization bounds using a new Bernoulli flow method. Based on joint work with Johannes Alt, Raphael Ducatez, and Joscha Henheik.</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/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Alexander Lytchak (Karlsruhe Institute of Technology)</div><div class="event_title">Metric-measure boundary and geodesic flow on singular spaces <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 disuss the existence of the geodesic flow and the invariance of the Liouville measure in non-smooth settings. Acentral role will play the so-called metric-measure boundary,  an objectfrom the geometric measure theory, which detects the boundary of aRiemannian manifold in the smooth setting and controls the average non-flatness of the space in more general situations. The talk will bebased on a joint work with Vitaly Kapovitch and Anton Petrunin and anongoing project with Daniele Semola and Stephan Stadler.</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_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">Dr. Isao Sauzedde (ENS de Lyon)</div><div class="event_title">Applying Symanzik\' program to the Abelian Higgs-Yang-Mills field in the continuum <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Dynkin\'s duality between Markov fields and Markov paths relate Gaussian free fields with Brownian paths. Symanzik\'s program for the Phi^4 field consists in using this relation to write the 2k-points functions of the Phi^4 fields as the expectation of the intersection local time of k Brownian bridges. In this talk, I will present this program in a different framework, that of the Abelian Higgs-Yang-Mills field in a planar domain, for which a complex scalar field interacts with a vector (gauge) field. In this framework, we will see that the role played by the intersection local time is played instead by the Amperean area of the paths, a random variable associated with the path which I will present during the talk. Due to the fact we consider two fields interacting with each other, it is necessary to take some partition functions into account. I will indeed explain how the partition function of a Gaussian field, in presence of an external magnetic field, can be written as an expectation of magnetic flux over a Brownian loop soup.The talk is freely based on two papers, one of which is joint with P. Perruchaud (ArXiv ids: 2402.00767 and 2412.16781). I will try to focus on presenting the big picture and I will stay rather informal at some stages.</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, April 2      </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">EPFL Lausanne</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">Séminaire de Topologie </a></div><br /><div class="event_speaker"> Michael Bleher (Universität Heidelberg)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">Single cells, population dynamics, and Euler characteristic profiles</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Euler characteristic profile (ECP) of a multifiltered simplicial complex records the Euler characteristic at each point in the filtration poset. While cruder than multiparameter persistent homology, ECPs are computationally much more tractable and often still sensitive enough to detect changes in the topology of the underlying data. For example, ECPs based on vector field data are able to differentiate between dynamical systems in 2 and 3 dimensions. In this talk, I present a recent project for similarly extracting dynamical information from high-dimensional point cloud data equipped with a vector field. The motivating application is single-cell RNA sequence data, where RNA velocity provides a proxy for the direction and rate of cellular state transitions. We construct multifiltered flag complexes where edge weights are derived from distances and velocities. On synthetic data generated by a stochastic model of gene expression dynamics with known ground-truth transition graphs, the resulting ECPs distinguish between competing state transition networks. Ultimately we want to use these ideas to investigate neural stem cell differentiation -- both in homeostasis and when it goes wrong, as in glioblastoma. This is joint work with Marta Marszewska, Justyna Signerska-Rynkowska, Pawe&#322; D&#322;otko, Anna Marciniak-Czochra, and Ana Martín-Vilalba.</div><div class="event_time">10:00 &bull; <a class="external" href="https://plan.epfl.ch/?room==CM%201%20517">EPFL Lausanne</a></div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Sylvain Crovisier (Université Paris-Saclay)</div><div class="event_title">Ergodic theory of surface diffeomorphisms</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_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">Dr. Mélodie Monod (Université Paris Dauphine-PSL)</div><div class="event_title"><a class="external" href="https://www.imsv.unibe.ch/research/talks/schedule/index_eng.html">Deep Survival Analysis</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Deep survival analysis has emerged as a powerful framework for modeling time-to-event data with complex, high-dimensional covariates. In this talk, we present two recent works in the field from both frequentist and Bayesian perspectives. We begin by reviewing state-of-the-art frequentist approaches, including recent developments such as TorchSurv, highlighting their modeling assumptions, strengths, and limitations—particularly with respect to uncertainty quantification. We then introduce NeuralSurv, the first deep survival model to incorporate Bayesian uncertainty quantification. Our non-parametric, architecture-agnostic framework captures time-varying covariate-risk relationships in continuous time via a novel two-stage data-augmentation scheme, for which we establish theoretical guarantees. For efficient posterior inference, we introduce a mean-field variational algorithm with coordinate-ascent updates that scale linearly in model size. By locally linearizing the Bayesian neural network, we obtain full conjugacy and derive all coordinate updates in closed form. In experiments, NeuralSurv delivers superior calibration compared to state-of-the-art deep survival models, while matching or exceeding their discriminative performance across both synthetic benchmarks and real-world datasets. Our results demonstrate the value of Bayesian principles in data-scarce regimes by enhancing model calibration and providing robust, well-calibrated uncertainty estimates for the survival function.</div><div class="event_time">15:15 &bull; Universität Bern, Hörsaal B77, ExWi, Sidlerstrasse 5, 3012 Bern</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, April 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/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Tom Hutchcroft (California Institute of Technology (Caltech))</div><div class="event_title">Dimension dependence of critical phenomena in percolation</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>    </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>';