var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-14"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-12"><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. 11</span>      <span style="float: right; text-align:right; width: 250px;">27.4 - 1.5.2026</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, April 27      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://www.unil.ch/dsa/en/home/menuinst/seminaires--evenements/research-seminars.html">Talks in Actuarial Mathematics </a></div><br /><div class="event_speaker"> Christian  Furrer  (Copenhagen, Denmark)</div><div class="event_title">Loss of earning capacity in Denmark – an actuarial perspective <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The purpose of insurance is to protect against uncertain events that lead to financial losses, which is first and foremost achieved by the pooling of diversifiable risks. Disability benefits play a crucial role in ensuring income stability for individuals by reducing financial vulnerability during periods with reduced earning capacity as well as supporting part-time employment. In this talk, I will describe challenges and opportunities related to risk assessment and mitigation for loss of earning capacity insurance, drawing on experience from Denmark and elsewhere. The presence of public benefits, claim settlement processes, and prevention initiatives introduces significant intricacy to the risk landscape. Accommodating this requires the development of innovative approaches from researchers and practitioners alike. Actuaries are uniquely positioned to lead the way, leveraging their domain knowledge and mathematical-statistical expertise to develop equitable, data-driven solutions that mitigate risk and enhance societal well-being. (Based on joint work with Kristian Buchardt and Oliver L. Sandqvist.)</div><div class="event_time">11:00 &bull; EPF Lausanne, Extranef 110</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"> Valentin  Imbach</div><div class="event_title">Linear Sketching meets Communication Complexity <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In our FOCS paper last year, we disproved a central conjecture stating that the Hamming-Distance problems witness a highly sought after separation in constant-cost communication complexity. We did this by noticing that these problems can be computed by applying a low-degree polynomial over constantly many, cleverly chosen linear sketches of Alice and Bob\'s inputs. In our paper, we also proposed a new candidate problem, coined "Rank-One", for the separation in question. Since then, we have been able to show that Rank-One can not be computed in this Linear Sketching model, bringing us a step closer to the desired separation. The proof involves the rank-method from algebraic complexity, en elegant application of the combinatorial Nullstellensatz, and a surprise appearance of Ramsey Theory.</div><div class="event_time">11:00 &bull; EPF Lausanne, INJ114</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/tggroup/doku.php?id=fables">Séminaire "Fables Géométriques" </a></div><br /><div class="event_speaker"> Sergey  Finashin (Ankara)</div><div class="event_title">Wall-Crossing Invariant Combinations of Welschinger Numbers for Rational Surfaces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We refine the real enumerative invariants not sensitive to chang- ing the real structure that we elaborated in our previous paper for del Pezzo surfaces, and extend these refined invariants to arbitrary rational surfaces.The definition requires a choice of an auxiliary conic bundle and of a Pin- structure.We prove independence of our invariants of these choices and provide recursive relations for computing these invariants.</div><div class="event_time">14:00 &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://math.ethz.ch/s/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Kai Cieliebak</div><div class="event_title">Symplectic quadrics in projective 3-space <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A well-studied and intriguing question concerns the relation between symplecticand algebraic surfaces in the projective plane. In ongoing work with Zhengyi Zhouwe address this question one dimension higher. In particular, we prove that eachdegree two symplectic hypersurface in complex projective space P3 is symplectomorphicto P1 times P1 with its standard structure. The proof uses the moduli space of nodalrational curves of degree two.</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"> Giorgio  Cipolloni</div><div class="event_title">The Spectral Form Factor for random matrices <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We prove that the Spectral Form Factor of Wigner matrices exhibits the universal dip-ramp-plateau phenomenon, a signature of quantum chaos widely used in physics and previously established only for a few integrable models.</div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Mathematisches Kolloquium </a></div><br /><div class="event_speaker">Prof. Dr. Ilya Molchanov (University of Bern)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Integer-valued valuations</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We obtain a complete characterization of planar monotone $\\sigma$-continuous valuations taking integer values, without assuming invariance under any group of transformations.Joint work with A. Ilienko and T. Visona</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 28      </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"> Jean-Claude  Hausmann  (UNIGE)</div><div class="event_title">On Geomorphisms <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A group homomorphism is called a geomorphism in dimension n  if it is the homomorphism induced on fundamental groups by a map between closed orientable n-manifolds, this map being of nonzero degree. In this talk, we discuss necessary and/or sufficient conditions for a group homomorphism to be a geomorphism (n>= 4).</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"> Antoine Pinardin (Universität Basel)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-antoine-pinardin-basel/">Finite abelian subgroups of the Cremona group of rank 3 - groups of K3 type.</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Very little is known about the classification of finite subgroups of Cremona in dimension 3 over the field of complex numbers. Let G be an abelian subgroup. If it is isomorphic to a product of subgroups of Cr(1) and Cr(2), G is called of product type. If G is a cyclic extension of a group that acts on a K3 surface, then it is called of K3 type. In a joint work with Loginov and Zhang, we classified groups of K3 type and conjecture that these two types are the only ones that can occur in Cr(3).</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_ne"><a class="external" href="https://unine.ch">Université de Neuchâtel</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/tggroup/doku.php?id=symplectic ">Geneva Neuchatel Symplectic Geometry Seminar (GeNeSyS)</a></div><br /><div class="event_speaker">Dr. Erman Cineli (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">Topological entropy and Floer theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk we discuss connections between Floer theory and dynamics of Hamiltonian systems, focusing on the barcode entropy of Hamiltonian diffeomorphisms and Reeb flows. Barcode entropy is the exponential growth rate of the number of not-too-short bars in the Floer or symplectic homology persistence module. The topological entropy bounds from above the barcode entropy and, conversely, the barcode entropy admits lower bounds coming from hyperbolic invariant sets. As a consequence, the two quantities are equal in low dimensions. The talk is based on joint work with Viktor Ginzburg, Basak Gurel and Marco Mazzucchelli.</div><div class="event_time">14:00 &bull; Université de Neuchâtel, Rue Emile-Argand 11, Room B217</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"> Isabel Stenger (Leibniz Universität Hannover)</div><div class="event_title">Beyond the Morrison-Kawamata cone conjecture  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The birational geometry of a projective variety is closely intertwined with the structure of its cones of divisors, in particular the nef cone and the movable cone. The Morrison–Kawamata cone conjecture predicts that the cones of effective nef divisors and effective movable divisors of a Calabi–Yau manifold are rational polyhedral up to the action of suitable automorphism groups. So far, the effective cone itself has played only a secondary role in this conjectural picture. We formulate an effective cone conjecture and show that, assuming the existence of good minimal models in dimension dim X, it is equivalent to the movable cone conjecture. As an application, we show that the movable cone conjecture holds unconditionally for the smooth Calabi–Yau threefolds introduced by Schoen. This is joint work with Cécile Gachet, Hsueh-Yung Lin and Long Wang.</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"> Martin  Ortiz (MPIM Bonn)</div><div class="event_title">Mod p de Rham cohomology of Shimura varieties and Serre\'s weight conjecture <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Serre\'s weight conjecture concerns mod p congruences of automorphic forms of different weights. In the context of Shimura varieties one can consider different spaces of mod p automorphic forms, e.g. via etale, coherent, or de Rham cohomology. I will explain a conjectural relation between etale and de Rham cohomology, and how the latter is related to coherent cohomology via generalized BGG resolutions. As opposed to the classical characteristic 0 picture, de Rham cohomology is not a direct sum of coherent cohomology groups,and only some pieces cut out by some differential operators contribute to it. Finally, I will mention one application of this approach to Serre\'s weight conjecture for GSp4. The whole talk will be illustrated by the example of the modular curve, and the Picard modular variety (G=GL3).</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 normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/seminaires/lie-sem/">Lie groups and moduli spaces </a></div><br /><div class="event_speaker"> Dario  Beraldo  (UniGE)</div><div class="event_title">Some contractibility results in birational geometry <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I\'ll discuss how some ideas from geometric representation theory can be used in birational geometry, for instance in the study of rationally connected varieties.</div><div class="event_time">15:00 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Dr. Charlotte Dietze (Laboratoire Jacques-Louis Lions Sorbonne Université)</div><div class="event_title">Spectral theory for singular Riemannian metrics <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We prove eigenvalue asymptotics and concentration of eigenfunctions of the Laplace-Beltrami operator for certain singular Riemannian metrics. This is motivated by the study of propagation of sound waves in gas planets. The talk is based on joint works with Yves Colin de Verdière, Maarten de Hoop and Emmanuel Trélat, and with Larry Read.</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_ne"><a class="external" href="https://unine.ch">Université de Neuchâtel</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/tggroup/doku.php?id=symplectic ">Geneva Neuchatel Symplectic Geometry Seminar (GeNeSyS)</a></div><br /><div class="event_speaker"> Peter Albers (Universität Heidelberg)</div><div class="event_title">Outer symplectic and length billiards at infinity <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We define outer symplectic and length billiards on vector spaces and discuss basic properties. The former is defined in arbitrary even dimensions, the latter in dimension 2. Both are symplectic, the former with respect to the standard symplectic form the latter not. However, both these discrete dynamical systems (actually their second iteration) far away from the billiard table can be approximated by continuous (and Hamiltonian) systems. The construction of these Hamiltonians involves in both cases symplectic polar duality. This is joint work with Ana Chavez Caliz, Lael Costa and Sergei Tabachnikov.</div><div class="event_time">16:00 &bull; Université de Neuchâtel, Rue Emile-Argand 11, Room B217</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat075.1">Zurich Graduate Colloquium</a></div><br /><div class="event_speaker">Zheng Fang (Institut für Mathematik, Universität Zürich)</div><div class="event_title">What is... random walk with relocation? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>The monkey walk is a self-interacting random walk that occasionally relocates to a site from its own past. I will discuss the simplest case where the relocation time is chosen uniformly from all its past times, and where between relocations the walk behaves like a simple random walk. This model provides an example of how relocation can drastically alter long-time behavior of the simple random walk, i.e., instead of diffusing on the usual \\(\\sqrt{n}\\) scale, the walk spreads only on the much slower \\(\\sqrt{\\log n}\\) scale. The talk will focus on intuition, the role of the uniform relocation rule, and the main ideas that turn the memory-driven walk into a problem about random recursive trees and its corresponding effective time. This talk is based on C&eacute;cile Mailler and Ger&oacute;nimo Uribe Bravo&rsquo;s work on random walks with preferential relocations and fading memory (2019).&lt;/p></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 29      </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"> Nicola Paddeu (Université de Fribourg)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde/detail/nicola-paddeu-fribourg/">Introduction to sub-Riemannian geodesics</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Abstract In this talk, we investigate the geometry of sub-Riemannian geodesics, starting from the fundamental definitions and guiding ideas that shape the field. After presenting the main notions and the central questions surrounding geodesics, we turn to the problem of regularity, highlighting its key features and discussing a representative result. No prior knowledge is required: the presentation is designed to be accessible, and particular emphasis will be placed on the connections between sub-Riemannian geometry and other areas of mathematics.</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">Leon Staresinic (Universität Zürich)</div><div class="event_title">The Topological Boshernitzan-Kornfeld Conjecture <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;">Interval Translations Maps (ITMs) are a natural generalisation of the well-known Interval Exchange Transformations (IETs). They are obtained by dropping the bijectivity assumption for IETs. As such, they are exactly the finite piecewise isometries of the interval. There are two types of ITMs, finite-type and infinite-type ones. They are classified by their non-wandering sets: it is a finite union of intervals for finite-type maps, and contains a Cantor set for infinite-type maps.&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;"><br> &lt;div>&lt;span style="color: #000000;">One of the basic questions in the field is: How prevalent is each type of map in the parameter space? In this work, we show that the set of finite-type maps contains an open and dense subset of the parameter space of ITMs with a fixed number of intervals, which resolves in positive the topological version of a long-standing conjecture due to Boshernitzan and Kornfeld.&lt;/span>&lt;/div> &lt;div>&nbsp;&lt;/div> &lt;span style="color: #000000;">This is a joint work with Kostiantyn Drach and Sebastian van Strien.&lt;/span>&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_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/forschung/mathematik/analysis/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker"> Shuchen Guo (University of Oxford, UK)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-shuchen-guo-university-of-oxford-uk/">Title T.B.A.</a></div><div class="event_time">14:15 &bull; Universität Basel</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"> Farell  Brumley</div><div class="event_title">Joint Linnik Problems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A well-known class of arithmetic equidistribution problems, attributed to Linnik, is concerned with periodic toric orbits on quaternionic varieties. Classical examples include the equidistribution of CM points of large discriminant on the modular surface and projections to the sphere of integer solutions to the sum of three squares. These problems were essentially solved by Duke using techniques in automorphic forms and analytic number theory. One can combine any two Linnik problems using a diagonal action of the torus, which encodes their simultaneous equidistribution (or disjointness). This creates a new set of problems, first put forward by Michel and Venkatesh, of considerably greater difficulty. We present new work with Valentin Blomer and Maksym Radziwi&#322;&#322; which uses an array of automorphic and analytic number theoretic techniques to prove the simultaneous equidistribution of two distinct Linnik problems, under a no-Siegel-zero type hypothesis. The latter assumption encodes the abundance of small split primes in quadratic field extensions, a property which interacts directly with competing approaches emanating from ergodic theory.</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_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"> William  Mance  (Poznan University)</div><div class="event_title">Normal Numbers <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Informally, a real number is normal in base 10 if each of the digits 0, 1, . . . , 9 shows up with frequency 1/10 in its decimal expansion, each pair of digits 00, 01, . . . , 99 shows up with frequency 1/100 in its decimal expansion and so on. There are many easily stated (but very difficult!) open questions revolving around normality. For example, even determining the normality of $\\pi$ in any base appears to be far out of reach of modern mathematics. Depending on the interest of the audience, we may explore connections between normal numbers and other areas of math such as ergodic theory, descriptive set theory, computability theory, probability theory, and others.</div><div class="event_time">14:15 &bull; EPF Lausanne, GR A3 32</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/forschung/mathematik/analysis/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker"> Jose A. Carrillo (University of Oxford, UK)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-jose-a-carrillo-university-of-oxford-uk/">Stein-Log-Sobolev inequalities for the continuous Stein variational gradient descent method</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Stein Variational Gradient Descent method is a variational inference method in statistics that has recently received a lot of attention. The method provides a deterministic approximation of the target distribution, by introducing a nonlocal interaction with a kernel. Despite the significant interest, the exponential rate of convergence for the continuous method has remained an open problem, due to the difficulty of establishing the related so-called Stein-log-Sobolev inequality. Here, we prove that the inequality is satisfied for each space dimension and every kernel whose Fourier transform has a quadratic decay at infinity and is locally bounded away from zero and infinity. Moreover, we construct weak solutions to the related PDE satisfying exponential rate of decay towards the equilibrium. The main novelty in our approach is to interpret the Stein-Fisher information, also called the squared Stein discrepancy, as a duality pairing between H?¹(Rn) and H¹(Rn), which allows us to employ the Fourier transform. We also provide several examples of kernels for which the Stein-log-Sobolev inequality fails, partially showing the necessity of our assumptions.</div><div class="event_time">15:00 &bull; Universität Basel</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">María Dolores Gómez Olvera (Universidad Rey Juan Carlos)</div><div class="event_title">Cryptographic Protocols Over Noncommutative Group Rings <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>Group rings represent a compelling alternative for the development of cryptographic protocols. They offer a versatile foundation for building primitives with potential post-quantum resilience.&lt;/p> &lt;p>In this talk, we will explore some recent advances in the design of secure protocols over noncommutative group rings. We will dicuss their fundamental algebraic properties and provide a security analysis against current cryptanalytic threats.&lt;/p></div><div class="event_time">15:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/sam/news-and-events/zhacm-colloquia">Zurich Colloquium in Applied and Computational Mathematics</a></div><br /><div class="event_speaker">Prof. Dr. Helmut Harbrecht (Universität Basel)</div><div class="event_title">Shape optimization under uncertainty <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This presentation aims to provide an overview of shape optimization in case of random input parameters. Besides the minimization of the expected objective, we also consider the minimization of failure probabilities. We show that in some situations the objective and its gradient are deterministic despite the random input. We can thus derive cheap, deterministic algorithms to minimize the objective. Several applications and numerical computations are given.</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://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">Sergi Sánchez Aragón (Universitat Autònoma de Barcelona)</div><div class="event_title">Simplex and MacDonald Codes Over Finite Chain Rings and Their Gray Map Images <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>A linear code of length \\(n\\) over a finite chain ring \\(R\\) with residue field \\(\\mathbb{F}_q\\) is a \\(R\\)-submodule of \\(R^n\\). A \\(R\\)-linear code is a code over \\(\\mathbb{F}_q\\) (not necessarily linear) which is the generalized Gray map image of a linear code over \\(R\\).&lt;/p> &lt;p>In this talk, we present some of the basic properties of linear codes over finite chain rings, as well as the tools used to study linearity of \\(R\\)-linear codes.&lt;/p> &lt;p>Finally, we introduce the construction of linear simplex and MacDonald codes of type \\(\\alpha\\) and \\(\\beta\\) over a finite chain ring, showing their properties and those of their Gray map images.&lt;/p></div><div class="event_time">16:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://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">Dr. Yujin Kim (California Institute of Technology)</div><div class="event_title">The low temperature SOS model above a wall and 1:2:3 scaling <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Random surfaces play a central role in probability and mathematical physics for decades. Physically, they often arise as models of interfaces: boundaries between distinct regions of space. The Solid-on-Solid (SOS) model is a canonical discrete model for interfaces separating stable (equilibrium) coexisting phases in three dimensions, such as the boundary of a solid that has crystallized in a liquid solution. In this talk, we present the fascinating geometry of the SOS model at "low temperature", conditioned to be non-negative ("above a wall": think of substration on a hard surface). In this setting, the SOS model resembles a wedding cake, being comprised of a sequence of shrinking, stacked layers whose boundaries form a collection of nested loops. Our work sheds light on the fluctuations of these loops away from their Wulff shape scaling limits, and in particular suggests a scaling limit for these fluctuations. Based on joint works with Patrizio Caddeo, Milind Hegde, Eyal Lubetzky, and Christian Serio.</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, April 30      </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"> Anna Sopena-Gilboy (UB Barcelona)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">A-infinity structures in complex geometry</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />For complex manifolds, there exists a refined notion of weak equivalence related to both Dolbeault and anti-Dolbeault cohomology. This class of weak equivalences naturally defines a stronger formality notion. In particular, satisfying the ddbar-Lemma property does not imply formality in this new sense. The goal of this talk is to introduce a novel operadic framework designed to understand this homotopical situation. I will present pluripotential A-infinity algebras as well as a homotopy transfer theorem based on this strong notion of weak equivalence. </div><div class="event_time">09:30 &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"> Amir Yehudayoff</div><div class="event_title">Neural networks and polytopes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />ReLU networks are a standard example of neural networks. We shall discuss the expressivity of neural networks with a focus on their depth. The plan is to start with a general introduction and a survey of basic results, including the duality between ReLU networks and a model for constructing polytopes. We shall then discuss polytopes and see how their properties can help to understand the depth of neural networks.  Based on joint works with Bakaev, Brunck, Hertrich and Stade.</div><div class="event_time">11:00 &bull; EPF Lausanne, INJ114</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"> Jérôme  Scherer (EPFL)</div><div class="event_title">The rational plus construction <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This is joint work with Ramon Flores and Guille Carrion. This talk will begin with a historical introduction to Quillen\'s plus construction (in integral homology) and its analogues for ordinary homology with coefficients. I will focus on the group theoretical background and a functorial description as a Bousfield localization. I will present the universal acyclic group (and its associated universal acyclic space) that Berrick and Casacuberta proposed in 1999 to achieve this. Our contribution is the construction of a rationally acyclic universal group (and associated space).</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_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"> Ana Péon (Nieto)</div><div class="event_title">Title T.B.A.</div><div class="event_time">14:15 &bull; EPF Lausanne</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> David  Rossel (Universitat Pompeu Fabra and Barcelona School of Economics)</div><div class="event_title">High-dimensional model selection: transfer learning and projected computation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We define as model selection the structural learning problem where the goal is to learn the subset of truly zero parameters in a probability model of interest, such as canonical generalized linear models, generalized additive models or graphical models. This is of course one of the most classical and fundamental problems in Statistics and Machine Learning. L0 penalization methods and their related Bayesian model selection counterparts have optimal mathematical properties for this task, yet much mainstream literature considers such methods to be either unnecessary or impractical. This talk discusses these two objections, and how to ameliorate the issues: is it useful to do this, and can we do this computationally?We first discuss how these methods can be useful, not only in theory but also in practice, and how to improve their performance via data integration (also called transfer learning). For example, sparse model recovery methods enjoy excellent asymptotic properties when certain sparsity and signal strength (betamin) conditions hold, but these assumptions often don\'t hold in some application domains. We show that data integration pushes the mathematical conditions under which consistent model recovery is possible.Regarding the second objection of computational impracticality, we review recent optimization and MCMC literature showing that, under somewhat strict sparsity assumptions, the computational cost scales linearly with the problem dimension (with high probability, asymptotically). A key practical issue is that such results assume that one can quickly score each candidate model (at constant cost), but even in least-squares the cost is (at least) quadratic in the model dimension and grows also with the sample size n. We propose a new class of projected model selection criteria that score models at constant cost, after an initial pre-processing step, and which enjoy the same asymptotic and practical performance as the costlier exact model scores.</div><div class="event_time">16:15 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/talks-in-financial-and-insurance-mathematics">Talks in Financial and Insurance Mathematics</a></div><br /><div class="event_speaker">Prof. Dr. Walter Schachermayer  (University of Vienna)</div><div class="event_title">A Komlos version of the Hsu-Robbins-Erdös law of large numbers <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The classical Hsu-Robbins-Erdös Theorem provides a sharpening of Kolmogoroff’s strong law of large numbers. It pertains to the i.i.d. case where boundedness in L^2 turns out to be a necessary and sufficient condition for complete convergence.We give a lacunary/hereditary version of this theorem in the spirit of Komlos. Interestingly, to obtain a necessary and sufficient version in our context, one necessarily has to go beyond martingale techniques as predicted some 40 years ago by David Aldous. Rather one has to rely on approximation by exchangeable sequences.Joint work with Istvan Berkes (Budapest) and Yannis Karatzas (New York).</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 1      </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_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"> Jean  Dolbeault  (Paris-Dauphine, France)</div><div class="event_title">Entropy methods and nonlinear flows for symmetry and stability results <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The lecture will be based on entropy methods for nonlinear diffusion equations with two main goals: 1. A review of various results of symmetry for the optimizers of nonlinear interpolation inequalities and a classification of some phase transitions between symmetry and symmetry breaking regimes; 2. Constructive methods for stability results in functional inequalities, including explicit results à la Bianchi-Egnell for Sobolev, log-Sobolev and related functional inequalities. Most of these results are based on a nonlinear carré du champ method.</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_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Jérémy Guéré (Université Grenoble Alpes)</div><div class="event_title">On the irrationality of cubic fourfolds <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />First, I will review the construction of atoms, beginning with anoverview at the formal level before addressing the technicaldifficulties that necessitate the use of non-Archimedean fields. Iwill also discuss the behavior of the Hodge structure under Iritani\'sblow-up formula.Then, I will introduce a new atomic invariant and provide the prooffor the following theorem: if a smooth complex cubic fourfold isrational, then its primitive cohomology is isomorphic, as a rationalHodge structure, to the shifted middle cohomology of a projective K3surface. The proof relies on explicit computations for surfaces that Iwill present.</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>';