var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-27"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-25"><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. 6</span>      <span style="float: right; text-align:right; width: 250px;">21.10 - 25.10.2024</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 21      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://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"> Ziyi Guan</div><div class="event_title">Relativized Succinct Arguments in the ROM Do Not Exist <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> relativized succinct argument in the random oracle model (ROM) is asuccinct argument in the ROM that can prove/verify the correctness ofcomputations that involve queries to the random oracle. We prove thatrelativized succinct arguments in the ROM do not exist. Theimpossibility holds even if the succinct argument is interactive, andeven if soundness is computational (rather than statistical). Thisimpossibility puts on a formal footing the commonly-held belief thatsuccinct arguments require non-relativizing techniques. Moreover, ourresults stand in sharp contrast with other oracle models, for which arecent line of work has constructed relativized succinct non-interactivearguments (SNARGs). Indeed, relativized SNARGs are a powerful primitivethat, e.g., can be used to obtain constructions of IVC(incrementally-verifiable computation) and PCD (proof-carrying data)based on falsifiable cryptographic assumptions. Our results rule outthis approach for IVC and PCD in the ROM.Based on https://eprint.iacr.org/2024/728, joint work with AnnalisaBarbara and Alessandro Chiesa</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://math.ethz.ch/s/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> Iakovos  Androulidakis (National and Kapodistrian University of Athens)</div><div class="event_title">On a conjecture by A. Weinstein <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Geometric (pre)quantization can be performed only for integral symplectic manifolds. In 1989 Alan Weinstein conjectured that using the notion of Diffeology, as well as Noncommutative Geometry methods, one might obtain the representations required to “quantise the unquantisable” from a torus bundle rather than a line bundle. In joint work with P. Antonini, we showed that the obstruction to integrality can be lifted by adding extra dimensions and passing to the diffeological category. In fact, the added dimensions force the C*-algebra associated with this construction to be nothing else than the crossed product algebra associated with a torus action.</div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Daniel  Kious  (Bath)</div><div class="event_title">Sharp threshold for the ballisticity of the random walk on the exclusion process <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 overview works on random walks in dynamical random environments. I will recall a result obtained in collaboration with Hilario and Teixeira and then I will focus on a work with Conchon--Kerjan and Rodriguez. Our main interest is to investigate the long-term behavior of a random walker evolving on top of the simple symmetric exclusion process (SSEP) at equilibrium, with density in [0,1]. At each jump, the random walker is subject to a drift that depends on whether it is sitting on top of a particle or a hole. We prove that the speed of the walk, seen as a function of the density, exists for all density but at most one, and that it is strictly monotonic. We will explain how this can be seen as a sharpness result and provide an outline of the proof, whose general strategy is inspired by techniques developed for studying the sharpness of strongly-correlated percolation models.</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 important"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Dr. Naoki Koseki (University of Liverpool)</div><div class="event_title">Gopakumar-Vafa invariants of local curves <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the 1990s, two physisists, Gopakumar and Vafa, proposed an ideal way to count curves in a Calabi-Yau threefold, that is conjecturally equivalent to other curve counting theories such as Gromov-Witten theory. It is very recent that Maulik and Toda gave a mathematically rigorous definition of GV invariants. In this talk, I will review a recent progress on the GV theory, including chi-independence for GV invariants on local curves and degree two GW/GV equivalence for some smooth curves with generic normal bundles. This is based on a joint work with T. Kinjo and another work with B. Davison. </div><div class="event_time">17:30 &bull; Zoom</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, October 22      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/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"> Laura Ciobanu (Heriot Watt University)</div><div class="event_title">On the conjugacy growth of Artin and Coxeter groups <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 new results on the conjugacy growth asymptotics and series in some classes of Artin and Coxeter groups. The methods utilized range from combinatorial to geometric, and the work is joint with Gemma Crowe, and separately with Anthony Genevois.</div><div class="event_time">10:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde">Bernoullis Tafelrunde</a></div><br /><div class="event_speaker"> Matteo Nesi (Basel)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde/detail/bernoullis-tafelrunde-matteo-nesi-basel/">Bernoulli Introducing Bounded Solutions 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 />abstract Afterwards, we eat lunch together. If you want to join, please sign here in until 20th of October.</div><div class="event_time">12:15 &bull; Universität Basel, Seminarraum 00.003, Spiegelgasse 1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat770.1">Oberseminar: Algebraische Geometrie</a></div><br /><div class="event_speaker">Dr. Alexey Ananyevskiy (LMU)</div><div class="event_title">Combing a hedgehog over a field <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A classical result in differential topology says that there are no nowhere vanishing vector fields on a 2-sphere. One may ask a similar question in algebraic geometry: does the tangent bundle to a sphere given by the equation x^2+y^2+z^2=1 over some field k have a nowhere vanishing section? Or more generally, when does the tangent bundle on an affine quadratic q=1 with q being a homogeneous degree 2 polynomial have a nowhere vanishing section? We give an essentially full answer to this question assuming that the quadric q=1 has a rational point. In particular, the 2-sphere x^2+y^2+z^2=1 over a field k has a nowhere vanishing vector field if and only if -1 is a sum of 4 squares in k. The proof uses a mixture of results from motivic homotopy theory, Chow-Witt rings and some constructions from the theory of quadratic forms. This is a joint work with Marc Levine.</div><div class="event_time">13:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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. Zineb  Hassainia  (NYU Abu Dhabi)</div><div class="event_title">On the desingularization of time-periodic vortex motion for the 2D Euler equations <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 vortex dynamics in the planar Euler equations, focusing on two key aspects. First, I will present a rigorous derivation of leapfrogging quartets of concentrated vortex patches near singular time-periodic relative equilibria of the point vortex system, using KAM theory. In the second part, I will show how to extend these techniques to desingularize time-periodic vortex orbits when the Euler equation is set in a generic bounded simply-connected domain. Specifically, we can prove that for a single point vortex, under certain non-degeneracy conditions, it is possible to desingularize most of these trajectories into time-periodic concentrated vortex patches.</div><div class="event_time">15:15 &bull; Online via Zoom (for the Zoom credentials please send an email to Laura Kobel) </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"> Ödül  Tetik (University of Vienna)</div><div class="event_title">On an inside out Pontryagin-Thom collapse map <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Lurie described how bordisms can be evaluated functorially (using factorization homology), given only the algebra of local observables in the bulk of a classical or quantum theory. I\'ll give a way, in depth 1, to extend this to an evaluation of defects. It is based on an "inside-out" version of the Pontryagin-Thom collapse map. The latter is a map associated to any defect submanifold, and was given originally in the case where the submanifold has a normal framing, realising the well-known equivalence between framed bordism groups and homotopy groups of spheres. It has an extension to cases where there is no normal framing. However, a similar extension of its inside-out version, which would let us evaluate defects with no normal framing, still needs to be found. </div><div class="event_time">15:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, October 23      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Prof. Dr. Sobhan Seyfaddini (ETH Zürich)</div><div class="event_title">The closing lemma and Lagrangian submanifolds <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will discuss the smooth closing lemma for Hamiltonian diffeomorphisms with invariant Lagrangians.  Based on joint work with Erman Cineli &amp; Shira Tanny.</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"> Aitor Iribar López (ETH Zürich)</div><div class="event_title">Complex abelian varieties and their moduli V <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The toroidal compactifications of A_g</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.unil.ch/dsa/en/home/menuinst/seminaires--evenements/research-seminars.html">Talks in Actuarial Mathematics </a></div><br /><div class="event_speaker"> Philippe Soulier</div><div class="event_title">Simulation and estimation of Gerber Shiu functions: a bootstrap approach <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We present estimation methods for values of Gerber-Shiu functions through simulation and bootstrap type algorithms.Joint work with Bartosz Glowacki.</div><div class="event_time">14:00 &bull; EPF Lausanne, Extranef 110</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ne"><a class="external" href="https://unine.ch">Universit&auml;t Neuchatel</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">Dr. Alessio Caminata (Università di Genova)</div><div class="event_title">Some Density Results on CSS and CSS-T Quantum Codes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We provide a concise introduction to CSS and CSS-T codes from the perspective of classical coding theory. We demonstrate that pairs of linear codes that yield a CSS code with good correction capability can be easily produced using a randomized construction when the cardinality of the base field is sufficiently large. Next, we prove that CSS-T codes exhibit the opposite behavior, showing that, under very natural assumptions, their rate and relative distance cannot be simultaneously large. We conclude with a simple construction of CSS-T codes derived from Hermitian curves. This is joint work with Elena Berardini and Alberto Ravagnani.</div><div class="event_time">15:00 &bull; Uni Neuchatel, B217</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"> Francesco Fournier-Facio (University of Cambridge)</div><div class="event_title">Bounded cohomology of transformation groups of R^n <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Bounded cohomology is a functional analytic analogue of group cohomology, with many applications in rigidity theory, geometric group theory, and geometric topology. A major drawback is the lack of excision, and because of this some basic computations are currently out of reach; in particular the bounded cohomology of some “small” groups, such as the free group, is still mysterious. On the other hand, in the past few years full computations have been carried out for some “big” groups, most notably transformation groups of R^n, where the ordinary cohomology is not yet completely understood. I will report on this recent progress, which will include joint work with Caterina Campagnolo, Yash Lodha and Marco Moraschini, and joint work with Nicolas Monod, Sam Nariman and Sander Kupers.</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. Fatih Ecevit (Dept. of Mathematics, Bo&#287;aziçi University)</div><div class="event_title">High-frequency BEM for sound-soft/hard multiple scattering and applications to the scattering amplitude <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We present our recent developments on the asymptotic expansions of high-frequency multiple scattering iterations in the exterior of sound-hard scatterers. As in the sound-soft case, these expansions lead into wavenumber dependent estimates on the derivatives (of all orders) of the multiple scattering iterations which, in turn, allow for the design and analysis of Galerkin boundary element methods (BEM) for their frequency independent approximation. We also present preliminary theoretical developments related to the accurate approximation of the remaining infinite tail in the Neumann series formulation of multiple scattering problems.Time permitting, in the second part of the talk, we present our preliminary results on the frequency independent approximation of the sound-soft scattering amplitude based on Bayliss-Turkel type local approximations to the Dirichlet-to-Neumann operator. Joint with: Y. Boubendir (NJIT) and S. Lazergui (NJIT)</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_ne"><a class="external" href="https://unine.ch">Universit&auml;t Neuchatel</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">Michael Schaller (Institut für Mathematik, Universität Zürich)</div><div class="event_title">BIKE and its Relation to Lattices over Polynomial Rings <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 study the BIKE cryptosystem. We will introduce a lattice over a polynomial ring which we construct from the public key. The private key is a vector in this lattice with special properties (being sparse). We study the properties of this lattice. Furthermore, using this framework we will reformulate a previous work about weak keys for BIKE in terms of this lattice and show that their weak keys correspond to shortest vectors in this rank 2 lattice. Instead of only finding the shortest vector, we are able to construct a reduced basis and generalize their attack. We also propose new problems which arise from the reformulation of their attack in terms of lattices.</div><div class="event_time">16:30 &bull; Uni Neuchatel, B217</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/seminar-on-stochastic-processes">Seminar on Stochastic Processes</a></div><br /><div class="event_speaker">Prof. Dr. Jean Bertoin (Universität Zürich, Switzerland)</div><div class="event_title">Graduate Workshop Reinforcement</div><div class="event_time">17:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room  H26</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, October 24      </div>      <div class="day_content">        <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/zahlentheorie/">Seminar Zahlentheorie</a></div><br /><div class="event_speaker"> Michael Stoll (Universität Bayreuth)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/number-theory-seminar-michael-stoll-universitaet-bayreuth/">Title T.B.A.</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Titel: Conjectural asymptotics of prime orders of points on elliptic curves over number fields Abstract: Define, for a positive integer~$d$, $S(d)$ to be the set of all primes $p$ that occur as the order of a point $P \\in E(K)$ on an elliptic curve $E$ defined over a number field $K$ of degree $d$. We discuss how some plausible conjectures on the sparsity of newforms with certain properties would allow us to deduce a fairly precise result on the asymptotic behavior of $\\max S(d)$ as $d$ tends to infinity. This is joint work with Maarten Derickx. Location: Spiegelgasse 5, Seminarraum 05.002</div><div class="event_time">14:15 &bull; Universität Basel</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"> Stepan Orevkov (Toulouse)</div><div class="event_title">Seifert forms and slice Euler characteristic of links <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The slice Euler characteristic of a link is bounded by $1-\\beta$ where $\\beta$ is what we call the {\\it Witt coindex} of a Seifert form which is defined to be $n-2k$ where $n$ is the rank of the Seifert form and $k$ is the maximal rank of a totally isotropic subspace  (this fact was proven by Levine and Taylor for knots, but the proof easily extends to links). No algorithm is known to compute $\\beta$. In 1969 Jerome Levine gave a computable necessary and sufficient condition for $\\beta$ to equal $0$. We give a computable necessary and sufficient condition for $\\beta$ to equal $1$. (Joint work with Vincent Florens.)</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://www.math.ethz.ch/mathematik-und-ausbildung/weiterbildung/kolloquium.html">Kolloquium über Mathematik, Informatik und Unterricht</a></div><br /><div class="event_speaker"> Hermann Biner</div><div class="event_title">Simulation dynamischer Systeme im Unterricht <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Wachstumsmodelle, ovales Billard, gekoppelte Pendel, Newton-Verfahren im Komplexen: Solche dynamische Systeme lassen sich mit einem (open-source) Programm simulieren. Die zugrundeliegende Mathematik ist in genügendem Masse elementar zugänglich, damit sie Anregungen für den erweiterten Mathematikunterricht bieten kann. Sei es in Freifächern, Intensivwochen oder auch für selbständige Arbeiten interessierter Schüler.</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">Dr. Lukas Gonon (Imperial College London)</div><div class="event_title">Deep learning for pricing: from applications to theory and back <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the past years, deep learning algorithms have been applied to numerous classical problems from mathematical finance and financial services. For example, deep learning has been employed to numerically solve high-dimensional derivatives pricing and hedging tasks, to provide efficient volatility smoothing or to detect financial asset price bubbles. Theoretical foundations of deep learning for finance, however, are far less developed.  In this talk, we start by revisiting some recently developed deep learning methods. We then present our recent results on theoretical foundations for approximating option prices, solutions to jump-diffusion PDEs and optimal stopping problems using (random) neural networks. We address neural network expressivity, highlight challenges in analysing optimization errors and show the potential of random neural networks for mitigating these difficulties. Our results allow to obtain more explicit convergence guarantees, thereby making employed neural network methods more trustable.Based on joint works with F. Biagini, A. Jacquier, A. Mazzon, T. Meyer-Brandis, C. Schwab, R. Wiedemann</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, October 25      </div>      <div class="day_content">        <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/seminar-in-numerical-analysis">Seminar in Numerical Analysis</a></div><br /><div class="event_speaker"> Andreas Veeser (University of Milan)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-in-numerical-analysis-andreas-veeser-university-of-milan/">Strictly equivalent a posteriori error estimators</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the context of finite element methods for boundary value problems, the goal of an a posteriori error analysis is to derive a so-called error estimator. Such an estimator should be a quantity that is computable in terms of the problem data and the finite element solution and equivalent to its error. Almost all error estimators available in literature, however, do not meet these requirements. Indeed, equivalence is typically verified only up to so-called (data) oscillations and their presence has been viewed as the price of computability. The talk will consist of two parts. The first part will argue that the infinite-dimensional nature of the problem data is an obstruction to computability, while the typical form of oscillations obstructs equivalence. In other words: the desirable but missing unspoiled equivalence is not only a technical problem but does not hold for the involved oscillations. The second part will then present the new approach to a posteriori error estimation proposed by [1]. Its resulting estimators are equivalent to the error and consist of two parts, where the first one is of finite-dimensional nature and thus computable, while the second one is a new form of data oscillation, which is always smaller that the old one and whose computability hinges on the knowledge of the problem data. This splitting of the error estimator is also convenient in guiding adaptive algorithms; cf. [2]. [1] C. Kreuzer, A. Veeser, Oscillation in a posteriori error estimation, Numer. Math. 148 (2021), 43-78 [2] A. Bonito, C. Canuto, R. H. Nochetto, A. Veeser, Adaptive finite element methods, Acta Numerica 33 (2024), 163-485. For further information about the seminar, please visit this webpage .</div><div class="event_time">11:00 &bull; Universität Basel, DMI, Spiegelgasse 5, 4051 Basel Seminarraum 05.001</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. Yannik Schuler (ETH Zürich)</div><div class="event_title">Refined mirror symmetry of local P2 <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will report on joint work with Andrea Brini in which we establish expected properties of the refined Gromov-Witten generating series of local P2 coming from B-model heuristics: modularity, the extended holomorphic anomaly equation, orbifold regularity and the leading order conifold asymptotics. The first three statements generalise results of Lho-Pandharipande and Coates-Iritani while the proof of the last property is new even in the unrefined limit. I will start off explaining why these four features are expected in the first place and will mention some of their consequences. Afterwards I will discuss aspects of their proof mostly focusing on the arguments proving the leading order conifold asymptotics.</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>';