var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-3"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-1"><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. 9</span>      <span style="float: right; text-align:right; width: 250px;">13.4 - 17.4.2026</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Spring Semester 2026</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, April 13      </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/s/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Jean-Philippe Chassé (Université de Montréal)</div><div class="event_title">On Lagrangian flux and monodromy <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Associated to any loop of Lagrangian submanifolds is a cohomology class of the basepoint: its flux. However, contrary to the symplectic setting, this does not define a morphism on the fundamental group of the space of Lagrangian submanifolds. I will explain how this can be rectified by considering the monodromy of the loop and how the algebraic properties of the ensuing flux-monodromy morphism are related to topological properties of the Hamiltonian orbit of the basepoint. Finally, I will provide explicit computations for certain Lagrangian tori, revealing novel structure in the associated fundamental groups. This is joint work with Joé Brendel and Rémi Leclercq.</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"> Kirill  Kovalenko</div><div class="event_title">For how long time evolution of chaotic or random systems can be predicted <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A classical insight in dynamical systems is that strongly chaotic deterministic dynamics often behaves, in many respects, like a random process. Most results in this direction are asymptotic: they describe what happens as time tends to infinity. In this talk, I will discuss a complementary question: how much can one say about finite-time behavior in chaotic and random systems?Focusing on first hitting probabilities for different parts of phase space, I will explain how this problem can be translated into symbolic dynamics, and in fair-dice-like systems into a combinatorial problem on words. Previous work [1] showed that, for words of the same length, there is an initial interval during which the hierarchy of first hitting probabilities is fixed, and that the length of this interval grows at least linearly with the word length. We prove that this growth is in fact exponential [2]. I will also briefly discuss the role of autocorrelation, the main ideas of the proof, and possible extensions.Joint work with Leonid Bunimovich.[1] M. Bolding and L. A. Bunimovich, Nonlinearity 32 (2019), 1731.[2] L. Bunimovich and K. Kovalenko, "For how long time evolution of chaotic or random systems can be predicted," arXiv:2512.16186, 2025.</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">Dr. Corentin Bodart (University of Oxford)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Subgroup membership and formal languages</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The intersection of Group Theory and Formal Language Theory has been fruitful in the last 50 years. I\'ll start by recalling some of the key results in the area, such as the characterisation of groups with regular and context-free Word Problem, and Lehnert\'s conjecture on groups with co-context-free Word Problem. In joint work with André Carvalho and Carl-Fredrik Nyberg-Brodda, we have been looking at similar languages related to another decision problem in groups: the Subgroup Membership Problem. I\'ll explain the toolbox we have been developing, apply it to examples and non-examples, and highlight some open problems along the way. No prior knowledge about formal languages is required.</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, April 14      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Dylan  Müller  (UNIGE)</div><div class="event_title">Special values and symmetries of the spectral zeta function of regular trees <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 spectral zeta function of regular trees. We determine its special values at integers and relate them with combinatorics of two-coloured Dyck words. We also show that they enjoy unexpected symmetries, mostly expressed at the level of their generating functions. These symmetries ultimately lead to a functional equation of the type \\( s \\) versus \\( 1-s \\).</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_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">Sofian Tur-Dorvault (Université de Montpellier)</div><div class="event_title">The motivic fundamental groupoid at tangential basepoints <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>If U is a smooth scheme over a subfield of the field of complex numbers, it is known from the work of Pierre Deligne and Alexander Goncharov that the prounipotent completion of the fundamental group of U^an based at any point has a motivic incarnation. More precisely, its coordinate ring arises as the degree-zero homology of the Betti realization of a Hopf algebra object in Voevodsky&apos;s triangulated category of motives. More generally, Deligne conjectured a similar property for the fundamental group based at a "point at infinity", i.e. the datum of a point x on a smooth compactification of U with normal crossings boundary, together with the datum of a tangent vector at x, normal to the boundary. While Deligne and Goncharov proved this conjecture in the case of the projective line minus three points, the general case remained open. In this talk, I will explain how logarithmic geometry, together with the notion of virtual morphisms between log schemes, allows one to construct the motivic fundamental group in full generality and to compute its realizations.&lt;/p></div><div class="event_time">13:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Xinxin Li</div><div class="event_title">A Semismooth Newton-Type Method for the Nearest Doubly Stochastic Matrix Problem <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 a semismooth Newton-type method for the nearest doubly stochastic matrix problem where the nonsingularity of the Jacobian can fail. The optimality conditions for this problem are formulated as a system of strongly semismooth functions. We show that the nonsingularity of the Jacobian does not hold for this system. By exploiting the problem structure, we construct a modified two step semismooth Newton method that guarantees a nonsingular Jacobian matrix at each iteration, and that converges to the nearest doubly stochastic matrix quadratically.</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_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. Shohei  Nakamura  (University of Birmingham)</div><div class="event_title">Inequalities for symmetric convex bodies via the Brascamp—Lieb theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This talk is based on joint work with Emanuel Milman (Technion) and Hiroshi Tsuji (Institution of Science Tokyo).The Brascamp–Lieb inequality (for multilinear functionals), originally introduced in 1976 as a generalization of Young’s convolution inequality, has since been found to be useful across a wide range of fields. For example, in 1991, within convex geometry, Ball showed that the Brascamp–Lieb inequality implies the reverse isoperimetric inequality. More recently, it has played a critical role in harmonic analysis, particularly in the context of the Fourier restriction conjecture and the Kakeya conjecture (e.g. Bennett—Carbery—Tao).In this talk, we focus on inequalities for symmetric convex bodies within convex geometry. Specifically, we consider the Blaschke–Santaló inequality and its multilinear version, a Talagrand-type inequality for the Wasserstein barycenter, the Gaussian correlation inequality and its strengthened version. On the analytic side, we also include a Laplace transform bound and an improvement of Borell’s reverse hypercontractivity.We will report on new developments obtained by reinterpreting this collection of inequalities from the perspective of the Brascamp–Lieb inequality.</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_dis"><a class="external" href="https://unidistance.ch">UniDistance Suisse</a></div><div class="event_type"><a class="external" href="https://distanceuniversity.ch/academic-events/mathematics-colloquium/">Mathematics Colloquium </a></div><br /><div class="event_speaker"> Ivan Dokmani&#263;  (Universität Basel, Switzerland)</div><div class="event_title"><a class="external" href="https://unidistance.ch/en/event/flowers-a-warp-drive-for-neural-pde-solvers">Flowers: A Warp Drive for Neural PDE Solvers</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We introduce Flowers, a neural architecture for learning PDE solution operators built entirely from multihead warps. Aside from pointwise channel mixing and a multiscale scaffold, Flowers use no Fourier multipliers, no dot-product attention, and no convolutional mixing. Each head predicts a displacement field and warps the mixed input features. Motivated by physics and computational efficiency,  displacements are predicted pointwise, without any spatial aggregation, and nonlocality enters only through sparse sampling at source coordinates, one per head. Stacking  warps in multiscale residual blocks yields Flowers, which implement adaptive, global interactions at linear cost. We theoretically motivate this design through three complementary lenses: flow maps for conservation laws, waves in inhomogeneous media, and a kinetic-theoretic continuum limit. Flowers achieve excellent performance on a broad suite of 2D and 3D time-dependent PDE benchmarks, particularly flows and waves. A compact 17M-parameter model consistently outperforms Fourier, convolution, and attention-based baselines of similar size, while a 150M-parameter variant improves over recent transformer-based foundation models with much more parameters, data, and training compute.</div><div class="event_time">16:30 &bull; <a class="external" href="https://fernuni.zoom.us/j/67733135300">UniDistance Suisse, Zoom</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/mat075.1">Zurich Graduate Colloquium</a></div><br /><div class="event_speaker">Dr. Kaloyan Slavov (ETHZ)</div><div class="event_title">What is ... the packing problem (over finite fields)? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;div style="font-size: 12pt; font-family: Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;" data-olk-copy-source="MessageBody">The classical Kakeya problem in Euclidean space asks how "small" a set can be if it contains a unit line segment in every direction. More generally, packing sets contain all images of a given set under a collection of transformations. Finite field analogues offer a combinatorial and algebraic perspective and motivate our work. &nbsp; &nbsp;&nbsp;&lt;/div> &lt;div style="font-size: 12pt; font-family: Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;">&nbsp;&lt;/div> &lt;div style="font-size: 12pt; font-family: Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;">We study sets E in the affine plane over a finite field that are invariant under a large subgroup R of SL_2. We prove that if |R|&gt;c|E|^{3/2}, then E must be contained in a line. The exponent 3/2 is sharp. We also state a conjecture in the Euclidean setting. This is joint work with Thang Pham and Le Quang-Hung.&lt;/div></div><div class="event_time">16:30 &bull; UZH Zentrum, Building KO2, Room F 150</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, April 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://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Dr. Tsviqa Lakrec (University of Geneva)</div><div class="event_title">Quantitative equidistribution of random walks by automorphisms on nilmanifolds <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p style="text-align: justify;">&lt;span style="color: #000000;">&lt;span style="caret-color: #ffffff; font-family: Helvetica; font-size: 12px; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;">Consider the random walk on a nilmanifold \\(X\\) induced by random automorphisms on some fixed starting point \\(x_0\\).<br>By a theorem of Bourgain-Furman-Lindenstrauss-Mozes, for \\(X\\) a torus and \\(x_0\\) irrational, the random walk approaches a uniform distribution at an exponential rate.&nbsp;<br>Benoist-Quint partially extends this to a nilmanifold, without giving any rate. Bekka-Guivarc&apos;h shows a spectral gap exists in this setting.<br>I will report on an upcoming work with Weikun He and Elon Lindenstrauss that generalizes these results and our previous result on Heisenberg nilmanifolds, giving an effective rate of equidistribution from random walks by automorphisms on 2-step nilmanifolds.&lt;/span>&lt;/span>&lt;/p></div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Jeremy Feusi (ETH Zürich)</div><div class="event_title">Tropical geometry and computations on the moduli space of abelian varieties <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We show how tropical geometry provides an effective tool forcohomological computations on (partial) compactifications of the modulispace of principally polarized abelian varieties. As an application, weextend the Fourier-Mukai transform to the torus rank 1 partialcompactification and use it to define a weight filtration on the Chowring of the partial compactification of the universal family. We alsodiscuss extensions to more general toroidal compactifications, whichallow us to study the moduli space of log abelian varieties andreinterpret results by Faltings-Chai.</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_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"> Marc Kegel (Universidad de Sevilla)</div><div class="event_title">The search for exotic knot traces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Every knot leaves a trace in the 4-dimensional world. The trace of a knot is the smooth 4-manifold obtained by attaching a 2-handle to the 4-ball along a knot in the 3-sphere. We will introduce the relevant notions and present a strategy to disprove the smooth 4-dimensional Poincaré conjecture by finding knot traces with certain exotic properties. In the second part of the talk, we will discuss different methods to search for such exotic knot traces. This talk will mainly be based on joint work with Jonathan Spreer.</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_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.imsv.unibe.ch/research/talks/colloquia/index_eng.html">Colloquia on Probability and Statistics </a></div><br /><div class="event_speaker">Dr. Rajita Chandak (EPFL)</div><div class="event_title"><a class="external" href="https://www.imsv.unibe.ch/research/talks/schedule/index_eng.html">The EM algorithm beyond classical Gaussianity</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The EM algorithm has been widely studied theoretically for finite Gaussian mixture models. However, the practical use cases of the EM algorithm span beyond these specialized theoretical models. In this talk we will cover recent advances in theory of the EM algorithm beyond the classical setting in two primary regimes. First, we will show the advantages of generalizing the EM algorithm to the federated (or distributed) learning regime wherein data heterogeneity poses a significant challenge to the applicability of classical statistical methods. We characterize the convergence rate of the EM algorithm under all regimes of data heterogeneity under finite mixtures of linear regressions. We show that rather than being a bottleneck, in some cases, data heterogeneity can suprisingly accelerate the convergence of iterative federated algorithms. Secondly, we will delve into the behaviour of the EM algorithm under mixtures of non-Gaussian densities. We will show in particular that even with sub-exponential tail decay, the convergence rates of the EM algorithm for mixture models do not suffer significantly, providing the initial foundations for extending many existing results to a larger class of mixture models.</div><div class="event_time">16:15 &bull; Universität Bern, Hörsaal B78, ExWi, Sidlerstrasse 5, 3012 Bern</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, April 16      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPFL Lausanne</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">Séminaire de Topologie </a></div><br /><div class="event_speaker"> Nadja Egner (UC Louvain)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">N-fold groupoids and n-groupoids in semi-abelian categories</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The notion of semi-abelian category, introduced by G. Janelidze, L. Márki and W. Tholen in 2002, generalizes that of abelian category, and captures the homological properties that the categories of groups, associative algebras, Lie algebras and cocommutative Hopf algebras over a field have in common. Internal structures behave surprisingly well in semi-abelian categories. For example, any internal reflexive graph admits at most one internal category structure, and the categories of internal categories and internal groupoids are isomorphic. Moreover, the category of internal groupoids is equivalent to the category of internal crossed modules. The notion of internal crossed module in any semi-abelian category was introduced by G. Janelidze in 2003, and recovers in particular the classical notion of crossed module of groups. The fact that the category of internal groupoids in a semi-abelian category is itself semi-abelian implies that also the category of internal n-fold groupoids is well-behaved. In this talk, I will prove that the full subcategory of internal n-groupoids in a semi-abelian category is a Birkhoff subcategory of the category of internal n-fold groupoids, and provide a simple description of the corresponding reflection for n=2. In the abelian context, the internal n-groupoids yield a torsion-free subcategory of the category of internal n-fold groupoids, and it is possible to characterize (higher) central extensions and compute generalized Hopf formulae for homology. Part of this talk is based on joint work with Marino Gran.</div><div class="event_time">10:00 &bull; <a class="external" href="https://plan.epfl.ch/?room==CM%201%20517">EPFL Lausanne</a></div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Sylvain Crovisier (Université Paris-Saclay)</div><div class="event_title">Ergodic theory of surface diffeomorphisms</div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Christopher  Chiu</div><div class="event_title">Differentials on the arc space and beyond <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The geometry of jet and arc spaces has long been studied in the context of birational geometry and motivic integration. In the first half we will recall some of the classical results as well as presenting some more recent developments on the schematic structure of the arc space. A key ingredient in these is de Fernex and Docampo\'s formula on the sheaf of differentials of jet and arc spaces. In the second half we will introduce a more categorical approach to their construction and discuss how to prove a similar formula for Greenberg schemes and arithmetic jet spaces. This talk covers work in progress with Tommaso de Fernex and Roi Docampo.</div><div class="event_time">14:00 &bull; EPF Lausanne, CM 1 517</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"> Léo  Mousseau (UNINE)</div><div class="event_title">Khovanov homology of positive links  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> In 2000, Khovanov introduced a homology theory for links whose graded Euler characteristic recovers the Jones polynomial. This so-called Khovanov homology is a powerful link invariant (e.g. it detects the unknot). In this talk, we will see how Khovanov homology provides an obstruction to a link being positive, and that it can detect fiberedness among positive links. This is based on joint work with Marc Kegel, Naageswaran Manikandan, and Marithania Silvero.</div><div class="event_time">14:15 &bull; Université de Genève, Conseil Général 7-9, Seminar Room, 8th floor,</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://stat.ethz.ch/events/zukost">ZueKoSt: Seminar on Applied Statistics</a></div><br /><div class="event_speaker"> Peter Grünwald (CWI and Leiden University)</div><div class="event_title">Beyond Neyman-Pearson: E-Values enable Testing with a Data-Dependent Alpha <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Classical hypothesis testing requires the significance level alpha be fixed before any statistical analysis takes place - violating this requirement is a mortal (yet frequently and often unwittingly committed!) sin in classical testing. The requirement is stringent:  it prohibits updating alpha during (or after) an experiment due to changing concern about the cost of false positives, or to reflect unexpectedly strong evidence against the null. Perhaps most disturbingly, witnessing a p-value p &lt;&lt; \\alpha vs p-just-slightly-smaller-than alpha has no statistical relevance for any downstream decision-making, making the evidence conveyed by a p-value (or a classical confidence interval) exceedingly hard to interpret. Here we show that tests based on e-values (wikipedia), a modern alternative to the. p-value, do allow for risk control with a data-dependent alpha. While e-values have been mostly associated with their suitability for anytime-valid tests and confidence, we consider their post-hoc validity at least as important. We show that, under a suitable (weak) definition of \'admissibility\', every admissible post-hoc valid test must be based on e-values. If the significance level is fixed in advance and the notion of \'admissibility\' is strengthened, this new result - really a complete class theorem -  reduces to the familiar Neyman-Pearson Lemma. Throughout the talk we illustrate our results using various types of e-values, including the newly defined "conditional" ones. Literature: G.  Beyond Neyman-Pearson: e-values enable hypothesis testing with a data-driven alpha. Proceedings National Academy of Sciences of the USA (PNAS), 2024.B. Chugg, T. Lardy, A. Ramdas, G. On Admissibility in Post-Hoc Hypothesis Testing. Intern. Journal of Approx. Reasoning, 2026. </div><div class="event_time">16:15 &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://k-os.math.ethz.ch">[K-OS] Knot Online Seminar</a></div><br /><div class="event_speaker"> Keegan Boyle (New Mexico State University)</div><div class="event_title">Involutions on the 4-sphere</div><div class="event_time">16:15 &bull; <a class="external" href="https://u-paris.zoom.us/j/87853056962">online</a></div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Prof. Dr. Frédéric Rousset (Université Paris-Saclay)</div><div class="event_title">Semiclassical limit of the cubic Nonlinear Schrodinger Equation for mixed states <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>We shall present a recent work on &nbsp;the semiclassical limit of NLS and Hartree type equations for infinitely many particles under suitable assumptions on &nbsp;the Wigner transform of the initial &nbsp;datum. The formal limit is a singular &nbsp;kinetic equation of Vlasov type &nbsp;where the force field is given by the gradient of the density.<br>We will recall previous results on the well-posedness of this type of kinetic equations<br>and explain how to get uniform estimates suitable to justify the semiclassical limit.<br>Joint work with Daniel Han-Kwan (Nantes)&lt;/p></div><div class="event_time">16:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 35/36</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"> Jean Pachebat (Ecole Polytechnique)</div><div class="event_title">Structure-Preserving Generative Models <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Neural generative models optimize global error measures but offer no guarantees on structural properties. This talk presents three settings where structure matters and standard methods fail, along with theory-guided fixes.(1) Extreme values: replacing Gaussian latent noise with Fréchet inputs in GANs enables universal approximation of tail dependence functions. (2) Order statistics: classical representations (Sukhatme, Schucany) decompose ranked data generation into neural-approximable blocks, with complexity independent of sample size. (3) Diffusion fine-tuning: Fisher\'s identity yields a gradient-free iterative tilting algorithm that steers generation via black-box rewards, with controllable error.Each contribution comes with approximation guarantees and experimental validation.</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, April 17      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Tom Hutchcroft (California Institute of Technology (Caltech))</div><div class="event_title">Dimension dependence of critical phenomena in percolation</div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div 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"> Ari Rappaport (ENSTA, Institut Polytechnique de Paris)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/event/details/seminar-in-numerical-analysis-ari-rappaport-ensta-institut-polytechnique-de-paris/">Towards robust discretizations and solvers for the time-harmonic Maxwell equations in complex media</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 we explore numerical methods to efficiently solve problems related to electromagnetic wave propagation. We focus on tailored discretizations and iterative solvers designed for robustness and parallel scalability. In the first part, we present the CHDG method, a hybridizable discontinuous Galerkin variant that employs hybrid variables consistent with impedance transmission conditions. This formulation leads to a contractive fixed-point solver composed of two cell-local operators, making the approach naturally parallelizable. We illustrate the method\'s performance using results from a 3D matrix-free implementation and discuss computational aspects. In the second part, we address Maxwell\'s equations with anisotropic material tensors for the permittivity and permeability. We present preliminary results toward extending a two-level domain decomposition analysis from the isotropic to the anisotropic setting and identify the key assumptions required for this generalization. For further information about the seminar, please visit this webpage .</div><div class="event_time">11:00 &bull; Universität Basel, Room 05.001, Spiegelgasse 5, 4051 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://sites.google.com/view/pm-seminar/home">Physical Mathematics Seminar</a></div><br /><div class="event_speaker"> Osama Khlaif</div><div class="event_title">Schubert line defects and the quantum K-theory of the partial flag <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 correspondence between 3d supersymmetric gauge theories living on \\mathbb{R}^2 \\times S^1 and quantum K-theory. This is a 3d uplift of the well-known relation between 2d gauged linear sigma models (GLSMs) with target variety X (a.k.a the Higgs branch) and the quantum cohomology of X. One way to state this correspondence is the following: half-BPS line operators (e.g. Wilson lines) wrapping the S^1 fibre are in one-to-one correspondence with coherent sheaves (e.g. vector bundles) on X. After reviewing these correspondences in general, I will focus on the case where X is a partial flag manifold. I will define a new set of half-BPS line operators, which I will call Schubert line defects, in terms of a supersymmetric quantum mechanical system coupled to the bulk 3d theory. In the infrared, I will argue that these lines flow to the Schubert classes of the quantum K-theory ring of X. The latter are defined in terms of the structure sheaves on the Schubert varieties in X, and they form a basis for the K-theory ring. Finally, using supersymmetric localization results, I will show in explicit examples how one can work out the quantum K-theory ring relations in terms of these line operators.</div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 8-02</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"> Beat Zurbuchen (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">Equidistribution and cohomological vanishing theorems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The equidistribution of Frobenius conjugacy classes acting on Galois representations is a corner stone of number theory going back to at least Dirichlets theorem on primes in arithmetic progressions. The goal of this talk is to give an introduction into such equidistribution theorems and to present recent equidistribution theorems for Tannakian monodromy groups. I will also discuss the cohomological vanishing theorems, which are a crucial input for the equidistribution theorems, in this talk.</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_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"> Frederick Moscatelli (University of Vienna)</div><div class="event_title">Stability of blowup for wave maps outside of symmetry <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The wave maps equation is a geometric, nonlinear wave equation that serves as a good toy model for more complicated wave equations, such as the Einstein equations. For spherical targets there exists in each supercritical dimension an explicit solution to the wave maps equation that blows up in finite time.Under a certain symmetry assumption, the stability of this solution has been established within the last 15 years or so. In this talk I will present the proof of stability without any symmetry assumptions.This is joint work with Roland Donninger.</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"> Sam Allen (KIT)</div><div class="event_title">Title T.B.A.</div><div class="event_time">15:15 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker"> Aitor Iribar López (ETH Zürich)</div><div class="event_title">Relations in the tautological ring of Mumford\'s compactification <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />On the universal family of abelian varieties, two key formulas have been known for a long time: [e] = \\theta^g/g! and \\theta^{g+1}=0, where $e$ is the class of the zero section and $\\theta$ is the symmetric theta divisor. The moduli space of abelian varieties can be partially compactified by torus rank 1 degenerations. These are semistable families that contain a semiabelian variety. Two basic questions arise: how can we express the class of the zero section in terms of simpler "tautological" classes? What are the relations between tautological classes?We use Fourier transforms and weight decomposition to address both questions. This is a continuation of the talk on Wednesday by J. Feusi, and it is based on joint work with Y. Bae, J. Feusi and S. Molcho.</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>';