var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-23"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-21"><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. 10</span>      <span style="float: right; text-align:right; width: 250px;">18.11 - 22.11.2024</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Autumn Semester 2024</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, November 18      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Tom Mrowka (Massachusetts Institute of Technology)</div><div class="event_title">Floer homology of three manifolds and applications to low dimensional topology <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Floer homology and the related invariants of 4-manifolds has given us deep insight in smooth differential topology in dimensions 3 and particularly 4. The theory has yielded insights like existence of exotic differentiable structures on 4 dimensional euclidean space, complex curves minimize genus in complex projective space, killing the Hauptvermuntung, there even appear to be connection to the 4 color map theorem. This course will build up Floer homology of three manifolds from scratch. The focus will be on Instanton Floer homology but we will mention other versions and develop applications as the course goes on.</div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 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.unil.ch/dsa/en/home/menuinst/seminaires--evenements/research-seminars.html">Talks in Actuarial Mathematics </a></div><br /><div class="event_speaker"> Andrii Ilienko (University of Bern)</div><div class="event_title">Small-scale asymptotic structure of ordered uniform k-spacings <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Uniform spacings are the distances between uniformly distributed points on the unit interval: 1-spacings correspond to adjacent points, while k-spacings are the distances between points separated by k &#8722; 1 others. I will present an apparently novel concept of local Poisson approximation for k-spacings, which provides detailed insights into their asymptotic behavior across the entire range of their possible lengths, including both extreme and moderate ones. The general results obtained using this approach are broad and encompass both classical and more recent findings, offering a unified framework for analyzing the asymptotic properties of k-spacings. </div><div class="event_time">14:00 &bull; EPF Lausanne, Extranef 126</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"> Dylan Cant (Paris-Saclay University, Paris)</div><div class="event_title">Spectral invariants and translated points <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will present recent work concerning a Floer theory persistence module associated to a Reeb flow and a contact isotopy \\phi. The persistence module depends on a filling of the contact manifold. The spectrum of the persistence module is contained in the set of lengths of translated points of \\phi relative the chosen Reeb flow. Under certain assumptions on the symplectic cohomology of the filling, the spectral invariants can be used to define a non-degenerate spectral norm on the contactomorphism group, and also spectral capacities for open sets. Various results, variations on the construction, and open questions concerning these structures will be discussed.</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"> Bruno Scharipa (Marseille)</div><div class="event_title"> Intersection of high dimensional critical percolation clusters and Branching random walk ranges  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Intersection of random walk ranges play a prominent role in different areas of probability theory and statistical physics. While this topic is now relatively well understood, at least for simple random walks on Euclidean lattices, much less is known for the intersection of critical branching random walks or critical percolation clusters. I will describe recent advances on this question. Joint (ongoing) work with Amine Asselah.</div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Mathematisches Kolloquium </a></div><br /><div class="event_speaker">Prof. Dr. Andrea Pinamonti (University of Trento)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Differentiability of Lipschitz functions in Euclidean spaces and Carnot groups</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the seminar, I will present some results concerning the fine differentiability properties of Lipschitz functions between Euclidean spaces and between Carnot groups.</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, November 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/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Gigliola Staffilani (Massachusetts Institute of Technology)</div><div class="event_title">Dispersive equations and wave turbulence theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this course we will investigate questions of weak turbulence theory by using as explicit example of wave interactions the solutions to periodic and nonlinear Schrödinger equations. We will start with Strichartz estimates on periodic setting, then we will move to well-posedness.We will then present two different ways of introducing the evolution of the energy spectrum. We will first work on a method proposed by Bourgain and involving the growth of high Sobolev norms. Then, we will give some ideas of how to derive rigorously the effective dynamics of the energy spectrum itself (wave kinetic equation), when one considers weakly nonlinear dispersive equations.  </div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 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/annonces/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Georgii  Veprev (Université de Genève)</div><div class="event_title">Entropy of subshifts and Rauzy graphs <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />It is well known that the entropy of a subshift of finite type can be computed as the logarithm of the Perron-Frobenius eigenvalue of a certain finite digraph constructed from the set of forbidden subwords which determines the subshift. For an arbitrary subshift, we associate a sequence of finite digraphs called the Rauzy digraphs of the subshift. We will show that the entropy of the subshift is equal to the limit of the logarithms of their Perron-Frobenius eigenvalues. If time permits, we will also discuss the limit of the remaining spectral values of Rauzy digraphs.</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_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"> Anastasia Istratuca (University of Edinburgh)</div><div class="event_title">Multilevel Monte Carlo Methods with Smoothing <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We consider the computational efficiency of Monte Carlo (MC) and Multilevel Monte Carlo (MLMC) methods applied to elliptic partial differential equations with random coefficients. We make use of the circulant embedding procedure to sample from the aforementioned coefficient. Then, to further improve the computational complexity of the MLMC estimator, we devise and implement the smoothing technique integrated into the circulant embedding method. This allows to choose the coarsest mesh on the first level of MLMC independently of the correlation length of the covariance function of the random field, leading to considerable savings in computational cost.</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_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"> Thibaut Lunet</div><div class="event_title">Title T.B.A.</div><div class="event_time">15:00 &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/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Gigliola Staffilani (Massachusetts Institute of Technology)</div><div class="event_title">Nonlinear blow up for supercritical defocusing NLS <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk I will present some recent results concerning non-radial implosions for compressible Euler and Navier-Stokes equation and non radial blow up for certain defocusing supercritical nonlinear Schrodinger equations. This work is a non radial generalization of the breakthrough results of Merle-Raphael-Rodnianski-Szeftel. The work presented is in collaboration with Gonzalo Cao-Laboratories, Javi Gomez-Serrano and Jia Shi.</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_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"> Jonathan Gruber (Erlangen)</div><div class="event_title">Award ceremony Schlaefli Prize, talk and apero.</div><div class="event_time">15:15 &bull; EPF Lausanne, CE1 5</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/seminaires/lie-sem/">Lie groups and moduli spaces </a></div><br /><div class="event_speaker"> Ilia Gaiur (Université de Genève)</div><div class="event_title">Higher Bessel Product Formulas: Explicit Examples of Multiplication Kernels. <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Higher Bessel functions are the solutions to the quantum differential equations for P^{N-1}. These functions are connected to the periods of the Dwork families via the Laplace transform, and the functions themselves are exponential integrals. In my talk, I will show how product formulas for these irregular special functions lead to other geometric differential equations associated with higher-dimensional families of algebraic varieties. I will discuss the geometric and algebraic properties of the periods for these families and later provide further perspectives on these correspondences.Work in collaboration with V. Rubtsov and D. van Straten.  </div><div class="event_time">15:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/labs/mathicse/">Computational Science and Engineering </a></div><br /><div class="event_speaker"> Martin  Skovgaard Andersen (DTU Orbit, Denmark)</div><div class="event_title">Optimization with rank-structured matrices <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Simple optimization methods commonly suffer from slow convergence near a minimizer, and yet such methods are often a de facto choice when dealing with large-scale problems with a large number of variables and/or large quantities of data. This talk presents some examples of how this issue can be addressed using rank-structured matrices as building blocks. Such matrices have a low-rank structure that admits a storage-efficient representation and fast algebraic operations (e.g., matrix-vector multiplication, factorization, etc.), and they arise frequently in engineering and data science, e.g., in applications that involve kernel functions. Examples include semiseparable (SS), hierarchical off-diagonal low rank (HODLR), and hierarchical semiseparable (HSS) matrices, all of which allow for linear or quasi-linear time and space complexity in key operations.</div><div class="event_time">16:15 &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://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">Catalina-Andreea Jurja (Universität Zürich)</div><div class="event_title">What is... fluid dynamics? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A mathematically rigorous description of fluid motion plays an important role, for example in understanding weather patterns or ocean dynamics. In this talk, we will derive the fundamentals equations of motions for an inviscid incompressible fluid -- the Euler equations. We will present known results as well as related open problems. Finally, we will discuss stability for 2D stratified flows relevant in geophysics.</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, November 20      </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/labs/cmgr/cmgr/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Hugo Parlier (University of Luxembourg)</div><div class="event_title"><a class="external" href="https://memento.epfl.ch/private/workspace/None/event/114259">Counting curves and crossing lemmas</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The crossing lemma for simple graphs gives a lower bound on the necessary number of crossings of any planar drawing of a graph in terms of its number of edges and vertices. Viewed through the lens of topology, this leads to questions about arcs and curves on surfaces such as how many crossings must a collection of m homotopically distinct curves on a surface of genus g induce.The talk will be about joint work with Alfredo Hubard where we explore some of these, using tools from the hyperbolic geometry of surfaces in the process.</div><div class="event_time">11:15 &bull; <a class="external" href="https://plan.epfl.ch/?room==CH%20B3%2031">EPF Lausanne, CH B3 31</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/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Prof. Dr. Daren Wei (National University of Singapore)</div><div class="event_title">Time Change Rigidity of Unipotent Flows <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Two non-isomorphic ergodic measure preserving flows can become isomorphic if one of the systems undergoes an appropriate time change. In this case we will say that these flows are Kakutani equivalent to each other. We say that an ergodic flow is loosely Kronecker if it is Kakutani equivalent to the straight line flow on (say) a two torus in an irrational direction (the exact direction is immaterial as these are all equivalent to each other). Landmark work of Ratner from the late 70s (that paved the way to her even more famous results on orbit closures and equidistribution of unipotent flows) establishes that 1) the horocycle flow on any finite area surface of constant negative curvature is loosely Kronecker. 2) the product of two such flows is not loosely Kronecker. It remained an open problem whether e.g. products of two horocycle flows are Kakutani equivalent to each other. We show unipotent flows are very rigid under time changes, and indeed unless the flows are loosely Kronecker, two unipotent flows are Kakutani equivalent if and only if they are isomorphic as measure preserving flows. This is a joint work with Elon Lindenstrauss</div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/tggroup/doku.php?id=fables">Séminaire "Fables Géométriques" </a></div><br /><div class="event_speaker"> Aloïs  Demory (Genève)</div><div class="event_title">Primitive real algebraic surfaces in 3-dimensional toric varieties  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The study of topology of real algebraic hypersurfaces is classically divided into two complementary directions : on one hand, finding restrictions on the topology of the real part of real algebraic hypersurfaces with given Newton polytope, and on the other hand, constructing real algebraic varieties with interesting topological properties of their real part. Primitive patchworking is a very fruitful combinatorial construction tool introduced by O. Viro that allowed to construct many maximal (with respect to the Smith-Thom inequality) real algebraic hypersurfaces in various smooth ambient spaces. The very specific topological properties of the hypersurfaces produced using this method are quite well studied in the case of hypersurfaces in smooth toric varieties. We present an ongoing attempt to extend some of these properties to primitive surfaces in arbitrary 3-dimensional toric varieties. As a consequence, new maximal surfaces in certain singular and non-singular toric 3-folds are constructed. </div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 6-13</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/hessbellwald-lab/seminar/epfl-topology-seminar-fall-2024/">Séminaire de Topologie </a></div><br /><div class="event_speaker"> Samuel Lavenir (EPFL)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/seminar/epfl-topology-seminar-fall-2024/">Fiberwise extensions of localizations and colocalizations</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, I will discuss the problem of extending functors to fiberwise constructions in the setting of higher topoi. I shall explain the relevance of such extensions both from a practical point of view, and through the lens of the internal logic of the topos. After discussing some known results about fiberwise extensions of localization functors, we will focus on the dual situation of cellularizations. We will see that extending such colocalizations is almost never possible, and relate our result to classical statements by Chachólski and Hernández. Along the way, emphasis will be put on the pertinence of higher categorical language to formalize the problem of fiberwise constructions.</div><div class="event_time">14:15 &bull; <a class="external" href="https://plan.epfl.ch/?room==CM%201%20517">EPF Lausanne</a></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"> Tommaso Cortopassi (Scuola Normale Superiore di Pisa)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-tommaso-cortopassi-scuola-normale-superiore-di-pisa/">An explicit Euler method for Sobolev vector fields with applications to the continuity equation</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We introduce a new stability estimate for comparing the regular Lagrangian flow of a Sobolev vector field to a piecewise affine approximation generated by an explicit Euler-like method, in the spirit of Crippa-De Lellis\'s estimates. We use this estimate to prove approximation results for solutions of the continuity equation, which can be represented as the push forward of the initial datum via the regular Lagrangian flow. We give two examples: a probabilistic one using Dirac deltas to approximate the initial datum and a deterministic one using a diffuse approximation instead. In both cases, we assume no regularity on the mesh partitioning the spatial domain.</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_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">Niklas Gassner (Universität Zürich)</div><div class="event_title">Codes over Rings, their Generic Decoding, and their use in Code-Based Cryptography <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Code-based cryptography is an area of post-quantum cryptography. Several code-based candidates compete in the standardization process of the National Institute of Standards and Technology. A common drawback of code-based cryptosystems is their often large public key size. An approach to decrease this size is the usage of convolutional codes. The idea behind this is that the public key sizes scales linearly in the maximum degree of its polynomial entries. However, thus far the complexity of generic attacks has been exponential in the size of the sliding generator or parity-check matrix. We give a framework which allows us to iteratively decode convolutional codes with information-set decoding. This method relies on the choice of several parameters whose choice affects the success probability of the algorithm and the running time, so we give tools to determine whether a choice of parameters is suitable. We also discuss reasons why the algorithm sometimes doesn\'t terminate and how to circumvent said issues. Finally, we use an implementation of our algorithm to attack two cryptosystem based on convolutional codes. For the first cryptosystem, we managed to recover about 74% of messages in our experiment, each in less than 10 hours. For the second proposal, we used our algorithm to give estimates on the running time and success probability. In two cases where the estimate was low we also verified the result by running the full algorithm. 80% of the experiments were successful and they indicate that the algorithm has a complexity significantly below the security estimates provided by the authors.</div><div class="event_time">15:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Ben Lowe (University of Chicago)</div><div class="event_title">Finiteness of Totally Geodesic Hypersurfaces in Negative Curvature <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />There is a broad body of work devoted to proving theorems of the following form: spaces with infinitely many special sub-spaces are either nonexistent or rare.  Such finiteness statements are important in algebraic geometry, number theory, and the theory of moduli space and locally symmetric spaces.  I will talk about joint work with Simion Filip and David Fisher proving a finiteness statement of this kind in a differential geometry setting.  Our main theorem is  that a closed negatively curved analytic Riemannian manifold with infinitely many closed totally geodesic hypersurfaces must be isometric to an arithmetic hyperbolic manifold.  The talk will be more focused on providing background and context than details of proofs and should be accessible to a general audience.</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_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://memento.epfl.ch/event/probability-and-stochastic-analysis-seminar/">Probability (and Stochastic Analysis) Seminar </a></div><br /><div class="event_speaker"> Greg  Pavliotis  (Imperial College London)</div><div class="event_title">Interacting particle systems and their mean field limit: phase transitions, control, and inference <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 present recent results on the quantitative study of stochastic interacting particle systems and of their mean field limit. We will start by exploring the relationship between the large N limit of the constant in the Logarithmic Sobolev Inequality and the presence or absence of phase transitions for the mean field PDE. We will then present methods for computing both stable and unstable stationary states of the mean field PDE and for steering the dynamics towards a chosen steady state using optimal control methodologies. Finally, we will study the problem of inferring the interaction potential from discrete space-time observations of the McKean-Vlasov PDE.</div><div class="event_time">16:00 &bull; EPF Lausanne, MA B2 485</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://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. Carlos Jerez-Hanckes (Universidad Adolfo Ibañez, Santiago, Chile)</div><div class="event_title">New Insights on Wave Scattering by Multiple Open Arcs: Lightning-Fast Methods and Shape Holomorphy <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 focus on solving time-harmonic, acoustic, elastic and polarized electromagnetic waves scattered by multiple finite-length open arcs in unbounded two-dimensional domain. We will first recast the corresponding boundary value problems with Dirichlet or Neumann boundary conditions, as weakly- and hyper-singular boundary integral equations (BIEs), respectively. Then, we will introduce a family of fast spectral Galerkin methods for solving the associated BIEs. Discretization bases of the resulting BIEs employ weighted Chebyshev polynomials that capture the solutions\' edge behavior. We will show that these bases guarantee exponential convergence in the polynomial degree when assuming analyticity of sources and arc geometries. Numerical examples will demonstrate the accuracy and robustness of the proposed methods with respect to number of arcs and wavenumber. Moreover, we will show that for general weakly- and hyper-singular boundary integral equations their solutions depend holomorphically upon perturbations of the arcs\' parametrizations. These results are key to prove the shape holomorphy of domain-to-solution maps associated to BIEs appearing in uncertainty quantification, inverse problems and deep learning, to name a few applications. Also, they pose new questions you may have the answer to!</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 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/seminar-on-stochastic-processes">Seminar on Stochastic Processes</a></div><br /><div class="event_speaker">Dr. Antoine Jego (EPFL, Lausanne (From Nov 2024: Ceremade, Paris Dauphine))</div><div class="event_title">Crossing exponent of the Brownian loop soup <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We study the clusters of loops in a Brownian loop soup in some bounded two-dimensional domain with subcritical intensity &#952; &#8712; (0, 1/2]. We obtain an exact expression for the asymptotic probability of the existence of a cluster crossing a given annulus of radii r and rs as r &#8594; 0 (s > 1 fixed). Relying on this result, we then show that the probability for a macroscopic cluster to hit a given disc of radius r decays like | log r|&#8722;1+&#952;+o(1) as r &#8594; 0. Finally, we characterise the polar sets of clusters, i.e. sets that are not hit by the closure of any cluster, in terms of log&#945;-capacity.</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">        Thursday, November 21      </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"> George McNinch (Tufts)</div><div class="event_title">Levi factors of linear algebraic groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let G be a linear algebraic group over the field k, and suppose that the unipotent radical U of G is defined and split over k (this condition always holds when k is perfect). A Levi factor of G is a k-subgroup M for which the quotient mapping &#960;:G &#8594; G/U determines an isomorphism &#960;:M &#8594; G/U. For any field k of positive characteristic, there are linear algebraic k-groups without Levi factors. We are interested in *descent* of Levi factors: if &#8467; is a finite separable field extension of k and if the group G_&#8467; obtained by base-change has a Levi factor, does G itself already have a Levi factor? In the talk, we will describe examples of *disconnected* G where this sort of descent fails. On the other hand, we’ll recall an older result which shows that descent holds if &#8467; is Galois over k with [&#8467;:k] invertible in k. Finally, we describe some sufficient conditions for descent using vanishing of the non-abelian cohomology set H^1(M,U). </div><div class="event_time">15:00 &bull; EPF Lausanne, CM 1 517</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/kolloquium">Perlen-Kolloquium</a></div><br /><div class="event_speaker"> Prof. Dr. Joachim Rosenthal (UZH)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/perlenkolloquium-prof-dr-joachim-rosenthal-uzh/">Towards a Standardization in Post-Quantum Cryptography</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Public key cryptography has been at the center of modern cryptography.  It is not only used for the exchange of secret keys but also for the authentication of entities on the Internet, for digital signatures and for the construction of digital currencies. Until a few years ago most public key systems were based on the hardness of factoring integers or on the hardness of the discrete logarithm problem in an elliptic curve. With the realization that a quantum computer would make many practically used public key cryptographic systems obsolete it became an important research topic to design public key systems which are expected to be secure even if a powerful quantum computer would exist. This new area of research is called post-quantum cryptography and there has been in the last couple of years a lot of efforts to come up with new standards to be used in everyday applications. The main part of the lecture will overview this recent development and will explain the underlying mathematical problems.</div><div class="event_time">16:15 &bull; Universität Basel, DMI, Spiegelgasse 5, 4051 Basel Seminarraum 05.002</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"> Giulio Belletti (Institut de Mathématiques de Bourgogne)</div><div class="event_title">Torsion in the Kauffman bracket skein module <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The skein module of a 3-manifold is a rich algebraic object whose elements are knots and links; it has many fascinating connections to representation theory, mathematical physics and the Jones polynomial. In this talk I will give a brief introduction to the topic, including discussing the sort of interesting problems that come up with these objects, and then I will focus on a recent joint work with R. Detcherry about the relationship between torsion in the skein module and interesting surfaces in the manifold.</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_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"> Roland  van der Veen   (Bernouilli Institute, University of Groningen)</div><div class="event_title">Plumbing according to 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 />We will illustrate how one can plumb together two embedded surfaces in three-space and why that matters to knot theory. Our main result is that the top coefficient of the Links-Gould invariant is multiplicative under plumbing. The Links-Gould invariant comes from the representation theory of quantum super algebras but we will not get technical about this. Instead we will use its cubic skein relation to illustrate the striking connection to surfaces, plumbing and fibered knots in an elementary fashion. This is joint work in progress with Daniel Lopez-Neumann.  </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_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"> Fabiana  De Cesare  (IHES France)</div><div class="event_title">Exploring Confinement in Anti-de Sitter Space. <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Anti-de Sitter space acts as an infra-red cutoff for asymptotically free theories, allowing interpolation between a weakly-coupled small-sized regime and a strongly-coupled flat-space regime. We discuss this interpolation in the context of Yang-Mills theories in AdS from the perspective of boundary conformal theories and its implications for the confinement/deconfinement transition. We find indications that at the transition a singlet scalar operator becomes marginal, destabilizing the deconfined phase existing at a small size and triggering a boundary renormalization group flow to a gapped, confined phase that smoothly connects to flat space. </div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Prof. Dr. Gigliola Staffilani (Department of Mathematics, MIT)</div><div class="event_title">The Schrödinger equation as inspiration of beautiful mathematics <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the last two decades great progress has been made in the study of dispersive and wave equations. Over the years the toolbox used in order to attack highly nontrivial problems related to these equations has developed to include a collection of techniques: Fourier and harmonic analysis, analytic number theory, math physics, dynamical systems, probability and symplectic geometry. In this talk I will introduce a variety of results using as model problem mainly the periodic 2D cubic nonlinear Schrödinger equation. I will start by giving a physical derivation of the equation from a quantum many-particles system, I will introduce periodic Strichartz estimates along with some remarkable connections to analytic number theory, I will move on the concept of energy transfer and its connection to dynamical systems, and I will end with some results on the derivation of wave kinetic equations.</div><div class="event_time">16:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room D 7.1</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://www.math.ethz.ch/mathematik-und-ausbildung/weiterbildung/kolloquium.html">Kolloquium über Mathematik, Informatik und Unterricht</a></div><br /><div class="event_speaker"> Emanuele Delucchi (Scuola universitaria professionale della Svizzera italiana)</div><div class="event_title">Die Geometrie der Kombinatorik: eine Dreiecksrhapsodie <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Pascals “Traité du triangle arithmétique” wurde zusammen mit “quelques autres petits traitez sur la mesme matiére” veröffentlicht: eine Perlenkette an verschiedenartigen Abhandlungen mit einem kombinatorischen Leitfaden. Diesen rhapsodischen Stil wollen wir weiterführen. Unser Startpunkt wird eine Eigenschaft des arithmetischen (“Pascal’schen”) Dreieckes sein, die womöglich zu den weniger bekannten zählt. Ausgehend davon werden wir eine kleine mathematische Reise unternehmen, die Themen wie Graphenfärbungen, Polynome mit reellen Nullstellen und Vektorgeometrie verbinden wird. Am Ende werden wir das Resultat illustrieren können, für das June Huh 2022 die Fields-Medaille erhalten hat.</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div 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. Yucheng Yang (University of Zurich)</div><div class="event_title">DeepHAM: A Global Solution Method for Heterogeneous Agent Models with Aggregate Shocks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We propose an efficient, reliable, and interpretable global solution method, the Deep learning-based algorithm for Heterogeneous Agent Models (DeepHAM), for solving high dimensional heterogeneous agent models with aggregate shocks. The state distribution is approximately represented by a set of optimal generalized moments. Deep neural networks are used to approximate the value and policy functions, and the objective is optimized over directly simulated paths. In addition to being an accurate global solver, this method has three additional features. First, it is computationally efficient in solving complex heterogeneous agent models, and it does not suffer from the curse of dimensionality. Second, it provides a general and interpretable representation of the distribution over individual states, which is crucial in addressing the classical question of whether and how heterogeneity matters in macroeconomics. Third, it solves the constrained efficiency problem as easily as it solves the competitive equilibrium, which opens up new possibilities for normative studies. As a new application, we study constrained efficiency in heterogeneous agent models with aggregate shocks. We find that in the presence of aggregate risk, a utilitarian planner would raise aggregate capital for redistribution less than in absence of it because poor households do more precautionary savings and thus rely less on labor income. Joint work with Jiequn Han and Weinan E</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, November 22      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Si Yi (Cathy) Meng (Cornell University)</div><div class="event_title">Gradient Descent on Logistic Regression with Non-separable Data and Large Step Sizes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We study gradient descent (GD) dynamics on logistic regression problems with large, constant step sizes. For linearly-separable data, it is known that GD converges to the minimizer with arbitrarily large step sizes, a property which no longer holds when the problem is not separable. In fact, the behaviour can be much more complex—a sequence of period-doubling bifurcations begins at the critical step size 2/&#120582;, where &#120582; is the largest eigenvalue of the Hessian at the solution. Using a smaller-than-critical step size guarantees convergence if initialized nearby the solution: but does this suffice globally? In one dimension, we show that a step size less than 1/&#120582; suffices for global convergence. However, for all step sizes between 1/&#120582; and the critical step size 2/&#120582;, one can construct a dataset such that GD converges to a stable cycle. In higher dimensions, this is actually possible even for step sizes less than 1/&#120582;. Our results show that although local convergence is guaranteed for all step sizes less than the critical step size, global convergence is not, and GD may instead converge to a cycle depending on the initialization.</div><div class="event_time">11:15 &bull; EPF Lausanne, INJ326</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"> Philippe Bolle (Avignon Université)</div><div class="event_title">On potentials whose level sets are orbits <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A level orbit of a mechanical Hamiltonian system is a solution of the equation of motion that is contained in a level set of the potential energy. In this talk we shall answer the following question : what can be said about smooth potential energy functions on the plane such that any point of the plane lies on a level orbit? We call such functions Levi potentials. We shall see that if a Levi potential is analytic, then it is necessarily radial. However any convex compact subset of the plane is the critical set of a Levi potential. The proof of these results relies on the properties of the inverse curvature flow.This is a joint work with M. Mazzuchelli and A. Venturelli. </div><div class="event_time">14:15 &bull; EPF Lausanne, MA B1 11</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"> Patrick Rebeschini (University of Oxford)</div><div class="event_title">Non-Euclidean Learning via Optimization Solvers and Stability <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Ridge regression and gradient descent are two foundational approaches in Euclidean learning, embodying statistical and algorithmic regularization, respectively. While extending this framework to non-Euclidean geometries has been extensively explored in statistics through methods such as M-estimation, with notable examples like the Lasso, the development of optimization solvers that achieve optimal statistical rates in non-Euclidean contexts remains less advanced.In this talk, we present recent progress in designing generalized gradient descent methods that attain optimal statistical rates in non-Euclidean settings. This includes linear regression where the ground-truth regressor lies within an ell_p ball, as well as general convex loss functions that are smooth with respect to ell_p norms. In the latter case, we resolve an open question posed by Attia and Koren in 2022 regarding the development of a black-box approach to transform algorithms into uniformly stable ones.(Based on joint work with Tobias Wegel and Gil Kur, as well as with Simon Vary and David Martínez-Rubio)</div><div class="event_time">15:15 &bull; EPF Lausanne, CM 1 517</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>';