var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-11"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-9"><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. 14</span>      <span style="float: right; text-align:right; width: 250px;">18.5 - 22.5.2026</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, May 18      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> Nils Carqueville (Universität Wien)</div><div class="event_title">Title T.B.A. <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />tba</div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Bernhard Albach (RWTH Aachen)</div><div class="event_title">Quadratic Growth of Geodesics on the Two-Sphere <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Given an arbitrary reversible Finsler metric on $S^2$, the question of how many closed geodesics such a metric admits has a long history. In this talk, we present a result showing that the number of prime closed geodesics grows at least quadratically with respect to length. The proof relies on an improvement of Franks’ theorem concerning the periodic points of area-preserving annulus maps, a model contact system, and the theory of cylindrical contact homology in the complement of a link.</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"> Martin  Hairer</div><div class="event_title">Construction of the non-Abelian Higgs model <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will review Parisi and Wu’s original motivation for introducing the ’stochastic quantisation’ procedure for QFT’s. 40 years after their insight, this approach is finally bearing fruit: it allows to provide a mathematically rigorous construction of the non-Abelian Higgs model. This is the first time that one of the natural QFT models has been constructed via stochastic quantisation without having first been established by other methods.</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. Daniel Bath (KI Leuven)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Geometry and singularities of configuration hypersurface</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Given a subspace of a based vector space, Bloch, Esnault, and Kreimer introduced configuration hypersurfaces/polynomials, which exhibits tension between the geometry of the embedding and the underlying matroid. The motivation comes from Feynman integrals where the Symanzik polynomial naturally appears. The recipe is: given a graph, make each edge a variable, and enumerate all spanning tree complements by summing the corresponding monomials. I will survey the construction of these configuration hypersurfaces and explain why the above graph construction is actually an example of a configuration polynomial. Then I will discuss recent work on the geometry of these hypersurfaces including, time permitting: what their dual varieties are; what their normalized Nash blow-ups are; what types of singularities they (and their normalized Nash blow-ups) have. This is based on joint work with various subsets of Denham, Schulze, Mustata, Walther. </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, May 19      </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"> Hervé  Hocquard  (Bordeaux & Genève)</div><div class="event_title">On various problems related to edge-colorings <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Edge coloring is a fundamental topic in structural graph theory. This talk explores the theoretical challenges of edge-coloring models that go beyond standard proper colorings. We will primarily focus on strong edge-coloring, where edges at a distance of up to two must receive distinct colors. By examining subcubic and planar graphs, we will review classic bounds—such as the well-known Erd&#337;s-Nešet&#345;il conjecture—and present recent structural results. Finally, we will discuss how these strict constraints can be generalized into the broader framework of packing edge-colorings, highlighting the tightness of these bounds alongside several open questions in the field.</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/forschung/mathematik/algebraische-geometrie/">Seminar Algebra and Geometry</a></div><br /><div class="event_speaker"> Julia Schneider (Université Bourgogne)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-julia-schneider-universite-bourgogne/">Atomic semi-orthogonal decompositions for derived categories of G-surfaces.</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 discuss a joint work with Alexey Elagin and Evgeny Shinder that lies at the intersection of birational and derived geometry. What kind of geometric information is encoded in the derived category of a variety, and how does this information behave under birational maps? We consider the case of surfaces equipped with a group action, and show that their derived categories admit a canonical (mutation-equivalence class of) semi-orthogonal decomposition that "behaves well" with respect to birational geometry. We call such decompositions "atomic". If time permits, I will discuss applications to (bi-)rationality questions. This talk is intended for non-experts of derived geometry; all notions will be explained.</div><div class="event_time">10:30 &bull; Universität Basel, Spiegelgasse 5, Seminarraum 05.002</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"> Rémi Abgrall (University of Zurich)</div><div class="event_title">"Active Flux" type approximation of hyperbolic equations: bound preservation, boundary conditions and non oscillatory properties <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, we will present further improvement of the PAMPA Algorithm which is a variant of the activeux method. More precisely, in the active flux method, due to Roe and co-authors, the time space discretisation are linked via the method of characteristics or some exact evolution operator, hence the name of the method because the flux a part of the solution. Here, we use the method of lines and we focus on the space approximation of the solution, in one and two dimensions, using unstructured or polygonal meshes. After a short introduction of the method which is a combination of finite volume and finite difference approximation that are interlaced in a particular manner, we will first present a simple bound preserving algorithm. This method is not specific to the PAMPA algorithm. However, the method has two difficulties: first being bound preserving does not mean that we are oscillation free, and second, handling the boundary condition is a bit obscure because part of the algorithm is inspired by finite difference. Using a connection with Discontinuous Galerkin methods, we will show how to solve both issues, and will provide several numerical examples that show the behaviour of the new algorithm.This work is a joint work with Drs Yongle Liu and Nikita Afanasiev (University of Zürich). I also acknowledge several inspiring and important discussions with Professor Kailiang Wu, SUSTech.</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_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"> Tamas Szamuely (Université de Pise)</div><div class="event_title">Finiteness theorems over infinite number fields <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />According to the Mordell--Weil theorem the group of points of an abelian variety over a number field is finitely generated, so in particular there are only finitely many points of finite order. I shall present various generalizations of the latter statement to certain number fields of infinite degree and also to higher degree étale cohomology groups. This includes older joint work with D. Rössler and recent joint work with D. Lombardo. </div><div class="event_time">14:15 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_dis"><a class="external" href="https://unidistance.ch">UniDistance Suisse</a></div><div class="event_type"><a class="external" href="https://unidistance.ch/en/mathematiques-et-informatique/recherche/number-theory/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_speaker"> Abinhandan  (IMJ-PRG)</div><div class="event_title">(phi, Gamma)-modules and syntomic complexes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the first part of the talk, we will look at the classification of p-adic crystalline representations of the absolute Galois group G_{Q_p} of the field of p-adic numbers Q_p, in terms of certain (phi, Gamma)-modules known as Wach modules. Then, we will define syntomic complexes with coefficients in a Wach module, and relate its cohomology to the Galois cohomology of the associated crystalline representation. In the second part, we will look at a generalisation of these results to the case of “small” affine algebras, i.e. we will classify p-adic crystalline representations of a certain etale fundamental group in terms of relative Wach modules, and compute the Galois cohomology of such representations using syntomic complexes. If time permits, we will also look at a globalisation of these statements to smooth proper p-adic formal schemes.</div><div class="event_time">15:00 &bull; <a class="external" href="https://tinyurl.com/UniDistanceNTSeminar">UniDistance Suisse, Zoom</a></div>        </div>        <div class="day_content_item cancelled"><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. Steve Hofmann (University of Missouri)</div><div class="event_title">CANCELLED: Title T.B.A.</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"> Nick Trefethen (Harvard University)</div><div class="event_title">QUADRATURE = RATIONAL APPROXIMATION  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Whenever you see a string of quadrature nodes, you can consider itas a branch cut defined by the poles of a rational approximation tothe Cauchy transform of a weight function.  The aim of this talkis to explain this statement and show how it opens theway to calculation of targeted quadrature formulas for all kindsof applications.  Gauss quadrature is an example, but it is justthe starting point, and many more examples will be shown.  I hopethis talk will change your understanding of quadrature formulas.This is joint work with Andrew Horning.</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, May 20      </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/studium/mathematik/doktorat/bernoullis-tafelrunde">Bernoullis Tafelrunde</a></div><br /><div class="event_speaker"> Beatrice Bernasconi (ETH Zürich)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde/detail/beatrice-bernasconi-eth-zurich/">Length functions in the 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 We define the Cremona group over the projective plane and some length functions and the respective dynamical invariants on its elements; we concentrate in particular on the Sarkisov length.</div><div class="event_time">12:15 &bull; Universität Basel, Lecture Room 117, Kollegienhaus</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Prof. Dr. Omri Sarig (Weizmann Institute of Science)</div><div class="event_title">Stochastic Properties for Measures of Maximal Entropy for Smooth Surface Diffeomorphisms <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&lt;span style="color: #000000;">Suppose \\(f\\) is a&nbsp;<u>general</u> infinitely&nbsp;differentiable topologically mixing surface diffeomorphism with positive topological entropy.&lt;/span>&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&nbsp;&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&lt;span style="color: #000000;">We show that&nbsp; the measure of maximal entropy is Bernoulli, and that all smooth observables exhibit exponential decay of correlations, the strong&nbsp; almost sure&nbsp; invariance principle,&nbsp; and (consequently) the central limit theorem and the law of the iterated logarithm.&lt;/span>&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&nbsp;&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&lt;span style="color: #000000;">The proof, joint with Crovisier and Buzzi,&nbsp; is based on a new dynamical property called "strong positive recurrence," which guarantees the existence of a symbolic model with spectral gap for the associated transfer operator.&nbsp;&lt;/span>&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&nbsp;&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&lt;span style="color: #000000;">&lt;span style="caret-color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; 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; text-decoration: none; display: inline !important; float: none;">(Joint with S. Crovisier &amp; J. Buzzi)&lt;/span>&lt;/span>&lt;/div> &lt;div style="caret-color: #ffffff; color: #ffffff; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;">&nbsp;&lt;/div></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/daco-seminar">DACO Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Shahar Mendelson (Texas A&M University, USA )</div><div class="event_title">On the structure of marginals in high dimensions <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let X be a centred random vector in \\R^d and consider the random matrix \\Gamma=\\sum_{i=1}^N &lt;X_i,->e_i, whose rows are independent copies of X. Given T \\subset S^{d-1}, how much of T\'s structure is captured by \\Gamma T? Our focus here is on fine notions of similarity - specifically, whether the (empirical) distributions of (&lt;X_i,\\theta>)_{i=1}^N are close in an appropriate sense to the distributions of &lt;X,\\theta>, uniformly in \\theta \\in T. The answer to this question was not known even when X=G, the standard gaussian. In this talk I will present the current state-of-the-art - which holds under minimal assumptions, and in particular leads to an (almost) optimal answer in the gaussian case. If time permits, I will present some of the questions that are still open. Joint work with D. Bartl.     </div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room F 26.1</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/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Alonso Beaumont (Rennes)</div><div class="event_title">The Margulis-Soifer property for the planar Cremona group <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In 1981, Margulis and Soifer established a remarkable property of finitely generated linear groups: such a group contains uncountably many maximal subgroups if and only if it is not virtually solvable. In particular, this yields the existence of maximal subgroups of infinite index in SL<sub>n</sub>(Z). We will show how their methods can be adapted to establish an analogous result for groups of birational transformations of the plane. This is based on joint work with Serge Cantat, Julie Déserti and Seung Uk Jang.</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. Christian Lubich (University Tuebingen)</div><div class="event_title">Time integration of tree tensor networks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The talk first presents some numerical experiments with time-dependent tree tensor network algorithms for the approximation of quantum spin system dynamics. It continues with the basics in the design of time integration methods that are robust to the typical presence of small singular values, that have good structure-preserving properties (norm, energy conservation or dissipation), and that allow for rank (= bond dimension) adaptivity and for parallelism. This discussion of basic concepts forms the main part of the talk and will be done for the smallest possible typeof tensor network differential equations, namely low-rank matrix differential equations, which are of interest in their own right. Once this nontrivial technically simplest case is understood, there is a systematic path to the extension of the integrators and their favourable properties to general tree tensor networks.This talk is based on joint work with many colleagues and former andpresent students, among which I wish to single out Othmar Koch for the first mathematical work on dynamical low-rank approximation (DLRA) in 2007, Ivan Oseledets for jointly discovering the first robust DLRA integrator in 2014(the projector-splitting integrator), Gianluca Ceruti and Jonas Kusch for jointly developing the Basis Update & Galerkin (BUG) integrators since 2022, and Hanna Walach, Gianluca Ceruti, Dominik Sulz and Charlotte Verhoeven forthe recent systematic extension from low-rank matrices to generaltree tensor networks both in theory and in increasingly efficientimplementations.</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://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. Giovanni Conforti (University of Padova)</div><div class="event_title">Propagation of weak log-concavity along generalised heat flows via Hamilton-Jacobi equations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A classical consequence of the Prékopa–Leindler inequality is that log-concavity is preserved along the heat flow. Beyond the classical heat semigroup, however, this phenomenon typically breaks down. In this talk, I will introduce a weaker notion of log-concavity that remains stable under generalized heat semigroups. I will show how this framework yields new log-semiconcavity estimates for ground states of Schrödinger operators with non-convex potentials, as well as propagation results for functional inequalities along generalized heat flows.I will also discuss how these weak log-concavity properties behave under conditioning and marginalization, extending classical ideas of Brascamp and Lieb beyond the log-concave setting. The main ingredient is a stochastic control perspective on quadratic Hamilton–Jacobi–Bellman equations, combined with a second-order analysis of reflection couplings along HJB characteristics.</div><div class="event_time">17:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room  H12</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, May 21      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">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"> Inés García-Redondo (University of Fribourg)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">Effective Resistance in Simplicial Complexes: Generalizations and Properties</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The concept of effective resistance, originally developed in electrical network theory, has become a powerful tool for studying the structure of graphs. It captures both direct and indirect connections between vertices, relates to random walks and spanning trees, and underlies applications ranging from graph sparsification to community detection. In recent years, several matrix expressions have been introduced aiming at extending the notion of effective resistance from graphs to simplicial complexes. In this talk, I will present a basis-free definition of effective resistance, rooted in the original definition motivated by physics, which unifies existing approaches, allows the extension of graph theoretic results, and reveals new structural insights.This is joint work with Claudia Landi, Sarah Percival, Anda Skeja, Bei Wang and Ling Zhou.</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://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Sorrachai  Yingchareonthawornchai</div><div class="event_title">A little clairvoyance is all you need <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In single-machine flow-time online scheduling, it is known that there is no competitive algorithm when you don’t know the jobs’ processing time (non-clairvoyant scheduling). One other hand, when you know the jobs’ processing time, shortest-remaining-processing-time first (SRPT) is optimal. We introduce the model of eps-clairvoyance where the processing time is unknown initially, but you learn the remaining time once the remaining time is eps-fraction of the processing time. We show that there is a (1/eps)-competitive algorithm in this setting, showing that there is a little clairvoyance is enough to circumvent the adversary.</div><div class="event_time">11:15 &bull; EPF Lausanne, BC329</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"> Livio Liechti (UNIFR)</div><div class="event_title">Minimal stretch factors of orientation-reversing pseudo-Anosov maps <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />It is a notoriously difficult problem to find the minimal stretch factor among all pseudo-Anosov maps of a given surface. In the classical case of closed orientable surfaces and orientation-preserving pseudo-Anosov maps, this problem is only solved in genus one and two. In this talk, we determine the orientation-reversing minimisers in genus up to four. This is based on joint work in progress with P. Dehornoy, E. Lanneau and Q. Perroud.</div><div class="event_time">14:15 &bull; Université de Genève, Conseil Général 7-9, 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/colloque">Colloque de Mathématiques </a></div><br /><div class="event_speaker"> Wolfgang Lueck (University of Bonn)</div><div class="event_title">A panorama of L^2- invariants <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Betti numbers of closed manifolds or finite simplicial complexes are classicalinvariants in algebraic topology. Atiyah proposed an L^2-version obtained fromthe universal covering and the action of the fundamental group using vonNeumann algebras.We will present the basic properties of these L ^2-Betti numbers without goinginto technical details and discuss interesting and striking applications totopology, algebra, group theory, and geometry which are both interesting for andeasy to explain to a general audience. If time allows, we will also introduce L^2-torsion which is the analogue of the classical Reidemeister torsion.</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"> Simeon Hellsten (University of Glasgow)</div><div class="event_title">Cobordism and Concordance of Surfaces in 4-Manifolds</div><div class="event_time">16:15 &bull; <a class="external" href="https://ethz.zoom.us/j/62106645974">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">Paolo Antonelli (GSSI)</div><div class="event_title">On the Initial-Boundary Value Problem for One-Dimensional Quantum Hydrodynamics <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>The Quantum Hydrodynamics (QHD) system is a fundamental model for quantum fluids, such as Bose-Einstein condensates and superfluid Helium. Mathematically, QHD is described by a compressible Euler system augmented by a dispersive quantum stress tensor. While the formal connection to nonlinear Schr&ouml;dinger (NLS) equations via the Madelung transformation is well-established, the rigorous, general analytical framework relies on the polar factorization method.<br>In the first part of this talk, I will review existing results for the Cauchy problem. Focusing on the one-dimensional case, I will discuss a wave-function lifting method that, under physically consistent assumptions, reconstructs a wave function directly from hydrodynamic data. This allows for a "genuine" hydrodynamic treatment of the theory without a priori reliance on the Schr&ouml;dinger picture. Furthermore, I will introduce a novel entropy related to the system&rsquo;s chemical potential, which provides the necessary a priori estimates to determine a compactness class for 1D weak solutions.<br>Finally, I will address the initial-boundary value problem (IBVP). I will motivate our choice of boundary conditions and their correspondence to the IBVP for the 1D NLS equation, then present a global existence result for finite-energy weak solutions. I will conclude by discussing potential applications and future directions for this research.&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">Dr. Jorge Yslas (University of Liverpool)</div><div class="event_title">Claim frequency modeling through phase-type mixture-of-experts regression <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 address the problem of modeling loss frequency using regression when the counts have a non-standard distribution. We propose a novel approach based on mixture-of-experts specifications on discrete phase-type distributions. Compared to continuous phase-type counter parts, this approach offers fast estimation via expectation-maximization algorithms, making it more feasible for use in real-life scenarios. Our model is both robust and interpretable in terms of risk classes and can be naturally extended to the multivariate case through two different constructions. Using simulated and real-world data, we showcase how our approach provides an effective solution for modeling loss frequency in non-standard situations.</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, May 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/s/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_title">Arithmetica Transalpina </div><div class="event_time"> &bull; Vienna</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"> 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"> Santanu Manna (IIT Indore, India)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/event/details/seminar-in-numerical-analysis-santanu-manna-iit-indore-india/">Modelling multi-porous media: from Gedanken experiments to wave propagation</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This talk presents a numerical framework for elastic wave propagation in fluid-saturated multi-porous media, with particular emphasis on multi-phase flow interactions and constitutive characterization. The governing equations are derived using Lagrangian mechanics, where the coupling between the solid matrix and multiple pore fluids is modelled through generalised dissipation terms based on a multi-phase extension of Darcy\'s law. This formulation enables a systematic representation of inter-phase momentum transfer and permeability effects across distinct pore networks. The effective elastic properties are identified via compliance-based Gedanken experiments, providing a physically consistent approach to determining macroscopic constitutive parameters from idealized mechanical responses. This allows the model to capture the influence of multiple interacting pore systems without relying on purely empirical assumptions. The resulting system supports multiple compressional wave modes associated with solid and fluid phases, along with a rotational mode in the solid skeleton. A finite element discretization is employed to simulate wave propagation, and the formulation is validated through dispersion analysis, stability considerations, and convergence studies. The proposed framework highlights the critical role of multi-phase Darcy coupling and experimentally motivated parameter identification in accurately modelling wave phenomena in complex multi-porous media. For full-length work: <a href="https://doi.org/10.1098/rspa.2023.0863," target="_blank">https://doi.org/10.1098/rspa.2023.0863,</a> Proc. A (2024) 480 (2290): 20230863. 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_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. Lorenzo  Sarnataro (University of Toronto)</div><div class="event_title">The Allen—Cahn equation and free boundary minimal surfaces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In recent years, the combined work of Guaraco, Hutchinson, Tonegawa, and Wickramasekera has established a min-max construction of minimal hypersurfaces in closed Riemannian manifolds, based on the analysis of singular limits of sequences of solutions of the Allen—Cahn equation, a semi-linear elliptic equation arising in the theory of phase transitions. In this talk, I will describe some recent boundary regularity results for such limit-interfaces, which provide the first steps towards an Allen—Cahn min-max construction of free boundary minimal hypersurfaces in Riemannian manifolds with boundary. This is based on joint works with Akashdeep Dey, Wenkui Du, Martin Li, and Davide Parise.</div><div class="event_time">12:15 &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://sites.google.com/view/pm-seminar/home">Physical Mathematics Seminar</a></div><br /><div class="event_speaker"> Francesca Mariani</div><div class="event_title">The ultracold black hole: classical and quantum aspects <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 consider a specific (near-)extremal limit of 4d Reissner–Nordström black holes (RNdS4&#8203;), namely the Ultracold black hole. This regime is obtained when the cosmological horizon of de Sitter space and the black hole horizons merge together into the most constrained solution that a RNdS4&#8203; black hole can have.After reviewing some essential features of this class of black holes, I will show how the Ultracold regime can be approached and highlight its classical properties.I will then consider two possible avenues to study its quantum properties. One approach consists in dimensionally reducing the 4d theory to 2d, relating the resulting effective action to a known regime of Sine Dilaton gravity describing flat gravity in 2d. The latter is dual to DSSYK, an exactly solvable quantum model. A second approach consists in computing one-loop corrections to the 4d Euclidean gravitational path integral, a procedure which involves subtleties that I will take into account.Finally, I will consider rotating Kerr black holes in de Sitter space and explore the Ultracold regime of this class of black holes. I will show that, at the classical level, perturbations away from extremality are described by a JT mode.</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_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"> Allen  Fang  (University of Muenster)</div><div class="event_title">Wave decay on slowly-rotating extremal Kerr-Newman black holes <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 decay of solutions to the wave equation on slowly-rotating Kerr-Newman black holes. The behavior of waves on extremal spherically symmetric black holes and axisymmetric waves on rotational extremal black holes has seen remarkable recent developments. I will discuss how these developments can be extended to the case of slowly-rotating Kerr-Newman, highlighting the similarities between the structure of the wave operator at null infinity and the structure of the wave operator at the extremal horizon.  </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_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"> Scott  MacLachlan</div><div class="event_title">Optimization and Learning in the Design of Preconditioners <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Computer simulation algorithms are a major tool in many areas of science and industry, particularly in areas where the behaviour of fluids or complex materials governs the physical processes of interest. A typical core of these tools is the numerical approximation of the solution to coupled nonlinear systems of partial differential equations, relying on nonlinear and linear solvers, such as Newton’s method and preconditioned Krylov iterations. Among the most effective preconditioners for these systems are multigrid and domain decomposition methods, which use multiscale representations of the systems to be solved to achieve linear-scaling complexity for the solution of these linear systems. These preconditioners typically rely on heuristics in their construction, to approximate solutions to underlying combinatorial (and other) optimization problems that specify parameters and other components of the preconditioners, based on the discrete problem to which they are being applied. In this talk, I will discuss the use of advanced optimization and machine learning techniques to approximately solve these optimization problems and the impact these techniques can have on advanced preconditioner design.</div><div class="event_time">15:00 &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_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"> Andrew  Duncan (Imperial College London)</div><div class="event_title">Computable Statistical Divergences for Functional Data <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Kernel-based discrepancies have found considerable success in constructing statistical tests which are now widely used in statistical machine learning.  Examples include Kernel Stein Discrepancy which enables goodness-of-fit tests of data samples against an (unnormalized)  probability density based on Stein\'s method.  The effectiveness of the associated tests will crucially depend on the dimension of the data.I will present some recent results on the behaviour of such tests in high dimensions,  exploring properties of the statistical divergence under different scaling of data dimension and data size.Building on this, I will discuss how such discrepancies can be extended to probability distributions on infinite-dimensional spaces.  I will discuss applications to goodness-of-fit testing for measures on function spaces and its relevance to various problems in uncertainty quantification.</div><div class="event_time">15:15 &bull; EPF Lausanne, CM 1 517</div>        </div>      </div>    </div>  </div>  <div id="sms_footer">    address: Alessandra Naldi Windler, Departement Mathematik, HG G 51.4, ETH Zurich, Raemistrasse 101, CH-8092 Zurich<br />    email: <a href="mailto:bulletin@math.ch">bulletin@math.ch</a> | phone: +41 44 632 3684 | url: <a href="https://math.ch">https://math.ch</a>    <br /><br /><img src="//www2.math.ethz.ch/smsjs/sms_logo.gif" width="150" alt="SMS/SMG Logo" title="SMS/SMG Logo" />  </div></div>';