var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-28"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-26"><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. 5</span>      <span style="float: right; text-align:right; width: 250px;">14.10 - 18.10.2024</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, October 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"> 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://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Artur Riazanov</div><div class="event_title">Better Boosting of Communication Oracles, or Not <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Suppose that you have a deterministic algorithm A that accesses anoracle O, and a probabilistic algorithm B that can answer O-queries withsome constant error. The conventional way to combine these two into asingle randomized algorithm is to replace each oracle query with log(#of oracle queries) invocations of the algorithm B to reduce error enoughso that the probability of an error in any oracle answer is constant bythe union bound.Can this simple strategy be improved? We study this question in thecommunication complexity setting and show that the additional log-factoris unnecessary if the oracle O computes Equality and is necessary if Ocomputes 1-Hamming distance. That has surprising implications for thedirect sum question in randomized communication complexity and yields anoracle separation between Equality and 1-Hamming distance.This is joint work with Nathan Harms</div><div class="event_time">11:00 &bull; EPF Lausanne, INJ114</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/studium/mathematik/doktorat/bernoullis-tafelrunde">Bernoullis Tafelrunde</a></div><br /><div class="event_speaker"> Elias Kurz (Neuchâtel)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde/detail/bernoullis-tafelrunde-elias-kurz-neuchatel/">Bernoulli Explains: The Generators of the Plane Cremona Group</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />abstract Afterwards, we invite the audience to lunch. If you want to join, please sign in here until 12th of October.</div><div class="event_time">12:15 &bull; Universität Basel, Seminarraum 05.002, Spiegelgasse 5</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"> Joé Brendel</div><div class="event_title">Product tori in S^2 x S^2 and Lagrangian packing <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A product torus in S^2 x S^2 is a Lagrangian torus obtained as the product of circles in the factors. The goal of this talk is to give a classification up to symplectomorphisms of such tori and illustrate that interesting things happen in case the symplectic form is non-monotone. Among other applications, we will answer a question about Lagrangian packings posed by Polterovich--Shelukhin. This is partially based on joint work with Joontae Kim. </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://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. Adrian Sauvaget (CNRS and Université de Cergy-Pontoise )</div><div class="event_title">Several problems about spin classes  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Many (partial) CohFTs in the moduli spaces of curves can be canonically lifted to the moduli space of spin structures. This leads to a refined study of these cohomology classes according to the sign (or Arf invariant) of the spin structure. We will review open problems and recent advances on the refined study of several partial CohFTs: Witten’s class, Double Ramification cycles, and strata of differentials. </div><div class="event_time">15:30 &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_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. Peter Feller (ETHZ)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Panorama around effective hyperbolization of 3-dimensional manifolds</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />After a brief survey of the study of low-dimensional manifolds -- spaces locally modelled on the topological space R^n for n&lt;5 -- we will discuss the idea of geometrization.  We will motivate geometrization by discussing uniformization of surfaces, and then talk about geometrization of 3-dimensional manifolds as initiated by Thurston: 3-manifolds are modeled on eight geometric model spaces, which include the Euclidean space (R^3 endowed with the ordinary Euclidean metric) and hyperbolic space H^3.As a consequence of Perelman\'s geometrization theorem it turns out that ``most\'\' 3-dimensional manifolds carry a hyperbolic structure, i.e. they are locally modelled on H^3. We will discuss this and then describe an approach to hyperbolization of most 3-dimensional manifolds that circumvents invoking Perelman\'s work. As an upshot, with this approach one can control many geometric quantities such as injectivity radius, diameter, and volume of hyperbolic structures.This talk is meant to be an overview; in particular, no knowledge of low-dimensional topology or hyperbolic geometry will be assumed. Any new research content is based on joint work with A. Sisto and G. Viaggi.</div><div class="event_time">17:15 &bull; Universität Bern, Sidlerstrasse 5, 3012 Bern, Room 228</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, October 15      </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"> Roland Roeder  (Indiana University)</div><div class="event_title">Expanding Blaschke Products for the Lee-Yang zeros on the Diamond Hierarchical Lattice <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In a classical work, Lee and Yang proved that zeros of certain polynomials (partition functions of Ising models) always lie on the unit circle. Distribution of these zeros control phase transitions in the model. We study this distribution for a special “Migdal-Kadanoff hierarchical lattice”. In this case, it can be described in terms of the dynamics of an explicit rational function in two variables. More specifically, we prove that the renormalization operator is partially hyperbolic and has a unique central foliation. The limiting distribution of Lee-Yang zeros is described by a holonomy invariant measure on this foliation. These results follow from a general principal of expressing the Lee-Yang zeros for a hierarchical lattice in terms of expanding Blaschke products allowing for generalization to many other hierarchical lattices. This is joint work with Pavel Bleher and Mikhail Lyubich.</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"> Dominic  Phillips (University of Edinburgh)</div><div class="event_title">MetaGFN: Exploring Distant Modes with Adapted Metadynamics for Continuous GFlowNets <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Generative Flow Networks (GFlowNets) are a class of generative models that sample objects in proportion to a specified reward function through a learned policy. They can be trained either on-policy or off-policy, needing a balance between exploration and exploitation for fast convergence to a target distribution. While exploration strategies for discrete GFlowNets have been studied, exploration in the continuous case remains to be investigated, despite the potential for novel exploration algorithms due to the local connectedness of continuous domains. Here, we introduce Adapted Metadynamics, a variant of metadynamics that can be applied to arbitrary black-box reward functions on continuous domains. We use Adapted Metadynamics as an exploration strategy for continuous GFlowNets. We show two continuous domains where the resulting algorithm, MetaGFN, accelerates convergence to the target distribution and discovers more distant reward modes than previous off-policy exploration strategies used for GFlowNets.</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/seminaires/lie-sem/">Lie groups and moduli spaces </a></div><br /><div class="event_speaker"> Oscar  Garcia-Prada  (Madrid)</div><div class="event_title">mini-course: Higher rank Teichmüller spaces and Higgs bundles <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 Teichmüller space of a compact surface can be identified with a connected component of the moduli space of representations of the fundamental group of the surface in PSL(2,R). Higher rank Teichmüller spaces are generalizations of this, which exist in the moduli space of representations of the fundamental group into certain real simple non-compact Lie groups of higher rank. As for the usual Teichmüller space, these spaces consist entirely  of discrete and faithful representations.  In this series of lectures, I will give a full classification of the groups for which higher rank Teichmüller spaces can exist, as well as a complex algebraic-geometric parametrization of these spaces in terms of Higgs bundles. This involves, in particular, the non-abelian Hodge correspondence, and the more recent Cayley correspondence developed in collaboration with Steve Bradlow, Brian Collier, Peter Gothen and André Oliveira (to appear in Annals of Mathematics, 2024, arXiv:2101.09377).</div><div class="event_time">15:00 &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://math.ethz.ch/s/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Dr. Stefano Decio (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">A unique continuation result for area minimizing currents <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Can two minimal surfaces touch each other to infinite order at a point without coinciding in a neighborhood of the point? Intuition from the theory of unique continuation for elliptic PDEs suggests this should not happen. Of course, part of the game here is to specify the notion of minimal surface. In joint work with Camillo Brena we give an answer to an instance of the question above: if an m-dimensional area minimizing integral current has infinite order of contact at a point with an m-dimensional surface with zero mean curvature then the current coincides with the surface in a neighborhood of the point.</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"> Dan Isaksen (Wayne State University )</div><div class="event_title">Computation in homotopy theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In part, the goal of homotopy theory is to compute algebraic invariants of topological objects.  Of particular interest is the computation of homotopy groups of spheres.  Any given result can typically be obtained in several completely distinct ways, using methods that have no visible consistency with each other.  It is remarkable that there exists a solution to this highly overdetermined problem.Like many areas of pure mathematics, machine computation can be applied to great effect in this endeavor.  I will discuss the history, current state of the art, and future prospects of machine computation in homotopy theory.</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, October 16      </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/seminaires/lie-sem/">Lie groups and moduli spaces </a></div><br /><div class="event_speaker"> Oscar Garcia-Prada  (Madrid)</div><div class="event_title">mini-course: Higher rank Teichmüller spaces and Higgs bundles <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 Teichmüller space of a compact surface can be identified with a connected component of the moduli space of representations of the fundamental group of the surface in PSL(2,R). Higher rank Teichmüller spaces are generalizations of this, which exist in the moduli space of representations of the fundamental group into certain real simple non-compact Lie groups of higher rank. As for the usual Teichmüller space, these spaces consist entirely  of discrete and faithful representations.  In this series of lectures, I will give a full classification of the groups for which higher rank Teichmüller spaces can exist, as well as a complex algebraic-geometric parametrization of these spaces in terms of Higgs bundles. This involves, in particular, the non-abelian Hodge correspondence, and the more recent Cayley correspondence developed in collaboration with Steve Bradlow, Brian Collier, Peter Gothen and André Oliveira (to appear in Annals of Mathematics, 2024, arXiv:2101.09377).</div><div class="event_time">10:00 &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://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Neel  Patel </div><div class="event_title">Limitations of Stochastic Selection with Pairwise Independent Priors <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Motivated by the growing interest in correlation-robust stochastic optimization, we investigate stochastic selection problems beyond independence.Specifically, we consider the instructive case of pairwise-independent priors and matroid constraints. We obtain essentially-optimal bounds for contention resolution and prophet inequalities.The impetus for our work comes from the recent work of Caragiannis et al., who derived a constant-approximation for the single-choice prophet inequality with pairwise-independent priors.For general matroids, our results are tight and largely negative. For both contention resolution and prophet inequalities, our impossibility results hold for the full linear matroid over a finite field. We explicitly construct pairwise-independent distributions which rule out an $\\omega(1/rank)$-balanced offline CRS and an $\\omega(1/\\log rank)$-competitive prophet inequality against the (usual) oblivious adversary.For both results, we employ a generic approach for constructing pairwise-independent random vectors — one which unifies and generalizes existing pairwise independence constructions from the literature on universal hash functions and pseudorandomness. Specifically, our approach is based on our observation that random linear maps turn linear independence into stochastic independence.We then examine the class of matroids which satisfy the so-called partition property — these include most common matroids encountered in optimization. We obtain positive results for both online contention resolution and prophet inequalities with pairwise-independent priors on such matroids, approximately matching the corresponding guarantees for fully independent priors. These algorithmic results hold against the almighty adversary for both problems.</div><div class="event_time">11:00 &bull; EPF Lausanne, INJ114</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">Dr. Katy Loyd (University of Maryland)</div><div class="event_title">Pointwise Ergodic Averages along Sequences of Slow Growth <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Following Birkhoff&#039;s proof of the Pointwise Ergodic Theorem, it is natural to consider whether convergence still holds along various subsequences of the integers. In 2020, Bergelson and Richter showed that in uniquely ergodic systems, pointwise convergence holds along the number theoretic sequence $\\Omega(n)$, where $\\Omega(n)$ denotes the number of prime factors of $n$, with multiplicities. In this talk, we will see that by removing this assumption, a pointwise ergodic theorem does not hold along $\\Omega(n)$. In fact, $\\Omega(n)$ satisfies a notion of non-convergence called the strong sweeping out property. We then further classify the strength of this non-convergence behavior by considering weaker notions of averaging. Time permitting, we will introduce a more general criterion for identifying slow growing sequences with the strong sweeping out property (based on joint work with S. Mondal).</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_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Dr. Sam Canning (ETH Zürich)</div><div class="event_title">Complex abelian varieties and their moduli IV <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Degenerating abelian varieties</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Dan Isaksen (Wayne State University)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/seminar/epfl-topology-seminar-fall-2024/">HF2-synthetic tools for computing stable homotopy groups</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />HF2-synthetic stable homotopy theory is a deformation of classical stable homotopy theory.  I will describe what this means in concrete terms, and I will demonstrate in practical terms how it helps us compute stable homotopy groups.</div><div class="event_time">14:00 &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"> Umberto Pappalettera (Universität Bielefeld)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-umberto-pappalettera-universitaet-bielefeld/">On anomalous regularity in Kraichnan\'s model of turbulent transport</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 present a new "anomalous regularisation" result for solutions of the stochastic transport equation \\partial_t \\rho + 	rc \\partial_t W ot \\nabla \\rho = 0, where W is a Gaussian, homogeneous, isotropic noise with lpha-H\\"older space regularity and compressibility ratio \\wp &lt; rac{d}{4lpha^2}. The proof is obtained by studying the local behaviour around the origin of solutions to a degenerate parabolic PDE in non-divergence form, which is of independent interest. Based on joint work with Theodore Drivas and Lucio Galeati.</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://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">Prof. Dr. Thomas Mettler (UniDistance Suisse)</div><div class="event_title">Flat extensions of principal connections and the Chern—Simons 3-form <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will introduce the notion of a flat extension of a connection on a principal bundle. Roughly speaking, a connection admits a flat extension if it arises as the pull-back of a component of a Maurer–Cartan form. For trivial bundles over closed oriented 3-manifolds, I will relate the existence of certain flat extensions to the vanishing of the Chern–Simons invariant associated to the connection. Joint work with Andreas Cap & Keegan Flood.</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://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. Gigliola Staffilani (Massachusetts Institute of Technology)</div><div class="event_title">A curious phenomenon in 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 talk we will use the periodic cubic nonlinear Schrödinger equation to present some estimates of the long time dynamics of the energy spectrum, a fundamental object in the study of wave turbulence theory. Going back to Bourgain, one possible way to conduct the analysis is to look at the growth of high Sobolev norms. It turns out that this growth is sensitive to the nature of the space periodicity of the system. I will present a combination of old and very recent results in this direction.</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. Alejandro Rosales Ortiz (Universität Zürich, Switzerland)</div><div class="event_title">Excursion theory for Brownian motion indexed by the Brownian tree <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We begin by introducing the notion of Brownian motion indexed by the Brownian tree. We will then present the main aspects of a theory, developed in two recent works with Armand Riera, that describes the evolution of this tree-indexed process between visits to 0. The theory applies to fairly general continuous Markov processes indexed by Lévy trees.  Despite the radically different setting, we will see that our results  share strong similarities with the celebrated Itô excursion theory for linear Brownian motion. If time permits, we will also discuss some applications to Brownian geometry. </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, October 17      </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"> Alexandru Pascadi (Oxford)</div><div class="event_title">The dispersion method and beyond: From primes to exceptional Maass forms <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The dispersion method has found an impressive range of applications in analytic number theory, from bounded gaps between primes to the greatest prime factors of quadratic polynomials. The method requires bounding certain sums of Kloosterman sums, using deep inputs from algebraic geometry and the spectral theory of GL2 automorphic forms. We\'ll give a broad outline of this process and discuss some of the key ideas in our work at arxiv.org/abs/2404.04239.</div><div class="event_time">14:15 &bull; EPF Lausanne</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"> Damien Gaboriau (CNRS ENS Lyon)</div><div class="event_title">Dynamique sur l\'espace des sous-groupes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Tout groupe discret dénombrable G admet une dynamique topologique canonique sur un espace 0-dimensionnel, à savoir l\'action par conjugaison sur son espace Sub(G) des sous-groupes. Le processus d\'élimination successive des points isolés délivre le noyau parfait K(G) dans Sub(G) et le rang de Cantor-Bendixson rk(G). Je passerai en revue quelques résultats allant de calculs de noyaux parfaits et de rangs de Cantor-Bendixson jusqu\'à des propriétés dynamiques de l\'action de G, tels la transitivité topologique, voire le chaos.Cela sera illustré par des exemples tels que les groupes de Baumslag-Solitar, des groupes de type hyperbolique,...  Il s\'agit de travaux en collaboration avec P. Azuelos, S. Bontemps, A. Carderi, F. Le Maître et Y. Stalder. </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"> Maggie Miller (The University of Texas at Austin)</div><div class="event_title">Seifert surfaces of alternating knots in 4D <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We show that any two same-genus, oriented, boundary parallel surfaces bounded by a non-split alternating link into the 4-ball are smoothly isotopic fixing boundary. In other words, a non-split alternating link bounds a unique Seifert surface up to isotopy in the 4-ball (and up to genus). This is joint with Seungwon Kim and Jaehoon Yoo.</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://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://ethz.ch/en/news-and-events/events/inaugural-farewell-introductory-lectures.html">Inaugural Lectures</a></div><br /><div class="event_speaker">Prof. Dr. Johanna Ziegel (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">How good is their best guess? Constructing and evaluating predictions</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">        Friday, October 18      </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/tggroup/doku.php?id=fables">Séminaire "Fables Géométriques" </a></div><br /><div class="event_speaker"> Stepan Orevkov (Toulouse)</div><div class="event_title">n algebraic curve with small boundary components in the 4-ball  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We construct an algebraic curve in a ball in C^2 which passes through the origin, and such that all its boundary components are arbitrarily small.</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 cancelled"><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"> Tobias Lamm (Karlsruhe Institute of Technology)</div><div class="event_title">CANCELLED: Title T.B.A.</div><div class="event_time">14:15 &bull; EPF Lausanne</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/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_speaker"> Christopher Birkbeck (University of East Anglia)</div><div class="event_title">Formalising the Regular Case of Fermat’s Last Theorem in Lean <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will discuss some recent joint work on formalising the regular case of Fermat’s Last Theorem in Lean. The regular case of FLT, where the exponent is a prime  p  that does not divide the class number of the  p-th cyclotomic field, has long been known to be much simpler than the full proof, making it a good target for formalisation. In my talk, I will explain what Lean is, why one would want to formalise mathematics, and some of the challenges encountered in this process. No prior knowledge of Lean or formalisation is required.</div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Yefeng Shen (University of Oregon and IHES)</div><div class="event_title"> Quantum spectrum and Gamma structures for flips <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Quantum spectrum and Gamma structures play key roles in Katzarkov-Kontsevich-Pantev-Yu’s proposal to extract birational invariants from quantum cohomology and Iritani\'s decomposition theorem for quantum D-modules of blowups. In this talk, we investigate these structures for standard flips in a much simpler setup, by restricting the quantum multiplication to a fiber curve direction. In this setup, we can show that both quantum spectrum and asymptotic behavior can be reduced from the local models, where the small I/J-functions are known explicitly. Using the asymptotic behavior of cohomology-valued Meijer G-functions, we obtain a decomposition of the cohomology of standard flips into asymptotic Gamma classes. This decomposition is compatible with the semi-orthogonal decomposition for standard flips constructed by Bondal-Orlov and Belmans-Fu-Raedschelders. The talk is based on work in progress joint with Mark Shoemaker.</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>';