var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-21"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-19"><img src="//www2.math.ethz.ch/smsjs/images/arrow_right.png"/></a></div>    <div class="sms_title">      <span style="float: left;">SMS</span>      <span>SWISS MATHEMATICAL SOCIETY</span>      <span style="float: right;">SMG</span>    </div>    <div class="sms_info">      <span style="float: left; width: 250px;">Bulletin no. 5</span>      <span style="float: right; text-align:right; width: 250px;">16.3 - 20.3.2026</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, March 16      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">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"> Swarnalipa  Datta</div><div class="event_title">Fourier Analysis on finite Abelian groups and its Applications <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A Boolean-valued function is a map from a domain D to a range of cardinality two, such as {&#8722;1, +1}, or {0, 1}. These functions play a central role in theoretical computer science, additive combinatorics, and several other areas. When the domain D is equipped with an algebraic structure, particularly that of a finite Abelian group, Boolean-valued functions become especially important for studying algorithms and complexity. Such settings allow us to investigate the Fourier analysis of Boolean functions, examine the structure of their Fourier spectra, and understand the behavior of their Fourier coefficients.Most prior work has focused on the case D=Z_2^n, the space of binary strings of length n. A natural question is whether these results extend to Boolean-valued functions defined over arbitrary finite Abelian groups. This talk will address several problems that we have generalized to this broader setting.Granularity: The Fourier sparsity s_f of f is the number of nonzero Fourier coefficients. When s_f is small, what can be said about the magnitude of the Fourier coefficients? Gopalan et al. (2011) showed that for Boolean functions on Z_2^n, every nonzero Fourier coefficient has absolute value at least 1/s_f.Upper bounds on Fourier dimension: The Fourier dimension r_f is the dimension of the Fourier support of f. Sanyal (2019) proved that r_f = O(\\sqrt{s_f} log s_f ). This was improved by Chakraborty et al. (2020), who showed that r_f = O(\\sqrt{s_f \\delta_f} log s_f ), where \\delta_f = Pr_x[f(x) = &#8722;1]. These results demonstrate that Boolean functions with small sparsity cannot have arbitrarily large Fourier dimension. Improved bounds for Chang’s lemma and Cohen’s idempotent theorem have also been obtained in the Z_2^n setting.Linear Isomorphism Testing: The linear isomorphism testing problem for Boolean functions over Z_2^n is also an important area of study. For A \\in Z_2^n×n, let f &#9702; A : Z_2^n &#8594; {&#8722;1, 1} be the function f &#9702;A(x) = f(Ax) for all x &#8712; Z_2^n. The Linear Isomorphism Distance between f : Z_2^n &#8594; {&#8722;1, 1} and g : Z_2^n &#8594; {&#8722;1, 1} is defined as dist_{Z_2^n}(f, g) = min_{A\\in Z_2^{n×n}: A is non-singular} \\delta(f &#9702;A, g). Assume that f and g satisfy the promise that either dist_{Z_2^n}(f, g)=0 or dist_{Z_2^n}(f, g) \\geq \\epsilon, the question of Linear Isomorphism testing is that of deciding which is the case. Additional investigations include the approximate degree of Boolean functions, the Fourier–Entropy Influence (FEI) conjecture, and related topics. A key challenge in extending results from Z_2^n to arbitrary finite Abelian groups is that general Abelian groups are not vector spaces, and their Fourier coefficients are complex numbers. Consequently, many structural properties used in the Z_2^n setting break down, making such generalizations nontrivial. The talk will highlight these challenges and discuss the main obstacles to developing analogous results over finite Abelian groups.The talk is based on the following works:(1) On Fourier analysis of sparse Boolean functions over certain Abelian groups [Chakraborty, Datta, Dutta, Ghosh, Sanyal], MFCS 2024(2) Testing Isomorphism of Boolean Functions over Finite Abelian Groups [Datta, Ghosh, Kayal, Paraashar, Roy], RANDOM 2025(3) Structure of Sparse Boolean Functions over Abelian Groups, and its Application to Testing [Chakraborty, Datta, Dutta, Ghosh, Sanyal](4) From Cubes to Groups: Fourier Structure, Character Decision Tree, and Learning on Abelian Groups  [Chakraborty, Datta, Ghosh, Sanyal]</div><div class="event_time">11:30 &bull; EPF Lausanne, INJ114</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"> Alberto Enciso (ICMAT )</div><div class="event_title">Diffeomorphism-based convex integration schemes for incompressible fluid flows <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will review how one can design convex integration schemes using volume-preserving diffeomorphisms to address problems that are typically not amenable to more traditional schemes. To illustrate this philosophy, we will consider the construction of rough steady Euler flows with certain prescribed topological properties and of Hölder continuous dissipative solutions to ideal MHD. The talk is based on joint work with Daniel Peralta-Salas and Javier Peñafiel-Tomás.</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"> Wojciech  De Roeck  (KU Leuven)</div><div class="event_title">Localization effects in many-body systems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> In the 50\'s, Phil Anderson introduced the concept of what is now known as "Anderson Localization" and what has become an inspiring topic both in physics and mathematics. Ever since, there has been a pertinent question about how this phenomenon manifests itself, if at all, for interacting particles.In particular, in the last two decades, there was a lively debate in the physics community about "Many-body localization". I will revisit this story, with an emphasis on mathematical results.In particular, in the preprint https://arxiv.org/abs/2408.04338 (still under revision), we prove that strongly disordered one-dimensional quantum chains have a conductance that is identically zero, at any temperature.</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://math.ethz.ch/s/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Octav Cornea (Montreal University)</div><div class="event_title">Non precompactness of some spaces of Lagrangian submanifolds <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This talk, based on joint work with Ambrosioni and Biran, will discuss some metric properties of  some spaces of Lagrangian submanifoldsendowed with the spectral metric. In particular, I will show how some naturalnotions of complexity in triangulated categories can be applied to sometriangulated persistence refinements of Fukaya categories to identifyexamples of such metric spaces that are not precompact.</div><div class="event_time">16:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Mathematisches Kolloquium </a></div><br /><div class="event_speaker">Prof. Dr. Tamas Keleti (ELTE Budapest)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Lipschitz images and dimensions</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Analyst\'s Traveling Salesman Problem asks for a characterization of those sets that can be covered by the Lipschitz image of [0,1]. We study the analogous problem obtained by replacing the interval with the Cantor set.Another motivation comes from the classical result that compact metric spaces are exactly the continuous images of the Cantor set. It is therefore natural to ask which metric spaces can be obtained as Lipschitz images of the Cantor set.As one might expect, dimension plays a central role. To make the talk self-contained, we review the definitions and basic properties of the most important notions of fractal dimension.It turns out that fractal dimensions are not only useful tools in this context, but our results also yield consequences for them. In particular, we derive that any reasonable notion of fractal dimension must lie between the Hausdorff dimension and the upper box dimension.</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, March 17      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/forschung/mathematik/algebraische-geometrie/">Seminar Algebra and Geometry</a></div><br /><div class="event_speaker"> Anastasia Vikulova (Basel)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-anastasia-vikulova-basel/">Smooth cubic surfaces over fields of positive characteristic</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk we discuss the most symmetric cubic surfaces over considered field. It is well-known that the most symmetric cubic surface over algebraically closed fields of characteristic zero is Fermat cubic surface. Obviously, over fields of positive characteristic the situation changes dramatically. We will discuss what happens to the automorphism group of smooth cubic surfaces over arbitrary fields.</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_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"> Kaixing  Cao  (University of Milano)</div><div class="event_title">A Motivic Comparison of p-adic Cohomology Theories for Rigid Analytic Varieties curves over anticyclotomic Zp-extensions at inert primes <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 develop a motivic approach to comparison theorems in p-adic Hodge theory. Using these methods, we establish a comparison isomorphism between de Rham--Fargues--Fontaine cohomology and overconvergent Hyodo--Kato cohomology. This result confirms that de Rham--Fargues--Fontaine cohomology realizes the conjectural vector bundle–valued cohomology theory on the Fargues--Fontaine curve envisioned by Fargues and Scholze. Furthermore, we show that, within the motivic framework, this construction coincides with the décalage-based theory introduced by Le Bras and Bosco.</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_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"> Sehyun Ji (University of Chicago)</div><div class="event_title">Implosion singularity of the inhomogeneous Landau equation with hard potentials <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Landau equation is a fundamental collisional kinetic model arising in plasma physics. In the spatially homogeneous setting, global well-posedness is known, and solutions exhibit strong regularizing effects. This naturally raises the question: can singularities arise due to spatial inhomogeneity?In this talk, I will present a construction of smooth, strictly positive initial data for the inhomogeneous Landau equation with &#947; \\in (\\sqrt{3}, 2] that develops a finite-time implosion singularity. Interestingly, the singularity manifests at the hydrodynamic level: macroscopic quantities such as density and temperature blow up, while the L^\\infty-norm of the distribution function remains uniformly bounded. Working in self-similar variables, our blow-up profile is asymptotically self-similar (Type II). The distribution function converges to a local Maxwellian, and the associated macroscopic fields approach to a smooth imploding solution of the compressible Euler equations.To our knowledge, this provides the first example of a collisional kinetic equation that is globally well-posed in the homogeneous setting but exhibits finite-time singularity formation for smooth inhomogeneous data. This is joint work with Jacob Bedrossian, Jiajie Chen, Maria Gualdani, Vlad Vicol, and Jincheng Yang.</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://www.math.uzh.ch/mat075.1">Zurich Graduate Colloquium</a></div><br /><div class="event_speaker">Julien Moy (Université d\'Orsay)</div><div class="event_title">What is... the spectral gap of a hyperbolic surface? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;div>The first nontrivial eigenvalue of the Laplacian on a closed Riemannian manifold (called the spectral gap) is a geometrical invariant that encodes many interesting properties of the manifold. Notably, it gives some quantitative information on the connectedness of the manifold, and on the rate of convergence to equilibrium of the heat flow.&lt;/div> &lt;div>&nbsp;&lt;/div> &lt;div>I will focus on hyperbolic surfaces, which are closed manifolds of dimension 2 with constant curvature -1. After defining these objects, I will review some results about the spectral gap in this setting. Recent developments provide probabilistic constructions of random surfaces that display optimal spectral gaps.&lt;/div></div><div class="event_time">16:30 &bull; UZH Zentrum, Building KO2, Room F 150</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://risklab.ethz.ch/news-and-events/walter-saxer-preis">Award ceremony "Walter Saxer-Versicherungs-Hochschulpreis"</a></div><br /><div class="event_speaker">Prof. Dr. Reto Knutti (Institute for Atmospheric and Climate Science, ETH Zurich)</div><div class="event_title">Talk on "Climate Change: Risks and Opportunities"</div><div class="event_time">18:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room E 5</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, March 18      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Francisco Arana-Herrera (Rice University)</div><div class="event_title">Chaos in polygonal billiards <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>&lt;span style="caret-color: #4d4d4d; color: #4d4d4d; font-family: gothambook, sans-serif; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; display: inline !important; float: none;">We discuss how chaos, i.e., sensitivity to initial conditions, arises in the setting of polygonal billiards. In particular, we give a complete classification of the rational polygons whose billiard flow is weak mixing in almost every direction, proving a longstanding conjecture of Gutkin. This is joint work with Jon Chaika and Giovanni Forni. No previous knowledge on the subject will be assumed.&lt;/span>&lt;/p></div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Dr. Gabriel Ribeiro (ETH Zürich)</div><div class="event_title">A moduli space of character sheaves <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let G be a connected commutative algebraic group over the complex numbers. In this talk, I will introduce a class of multiplicative line bundles with flat connection on G, called character sheaves, and describe the construction and geometry of their moduli space.These objects are inspired by &#8467;-adic local systems that play a central role in modern analytic number theory. The construction of the moduli space relies on the so-called de Rham space, which provides a stack-theoretic approach to de Rham cohomology.If time permits, I will explain how the geometry of this moduli space leads to generic vanishing theorems for de Rham cohomology, and how these results give rise to a common framework for differential and difference Galois theory.</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Marc Magaña (Universitat Autònoma de Barcelona)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-marc-magana-universitat-autonoma-de-barcelona/">Continuity of the solution map to some active scalar equations in Hölder and Zygmund spaces</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, we explore the continuity properties of the solution map, in Hölder and Zygmund spaces, to a class of nonlinear transport equations in R^n. The velocity field in these equations is given by the convolution of the density with a kernel that is homogeneous of degree -(n-1) and smooth away from the origin. This setting encompasses significant models, including the 2D Euler equations and the 3D surface quasi-geostrophic (SQG) equations.</div><div class="event_time">14:15 &bull; Universität Basel, Spiegelgasse 5, Seminarraum 05.002</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Kathryn Hess Bellwald (EPFL)</div><div class="event_title">Hochschild homology: the universal shadow <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Hochschild homology has proved to be an important invariant in algebra and homotopy theory, in particular due to its relevance in algebraic K-theory and fixed point theory, leading to the development of numerous variants of the original construction. Ponto\'s theory of shadows provides a bicategorical axiomatization of Hochschild homology-type invariants, which captures the essential common properties of all known variants of Hochschild homology, such as Morita invariance.  In recent work, Nima Rasekh and I clarified the relationship between shadows and Hochschild homology. After extending the notion of Hochschild homology to bicategories in a natural manner, we proved the existence of a universal shadow on any bicategory B, taking values in the Hochschild homology of B, through which all other shadows on B factor. Shadows are thus co-represented by a bicategorical version of Hochschild homology. Using the universal shadow on the free adjunction bicategory, we established a universal Morita invariance theorem, of which all known cases are immediate corollaries.   In this talk I will give an overview of my work with Rasekh and provide relevant examples of shadows, including the free loop space construction, then discuss potential generalization and extensions of our results.</div><div class="event_time">15:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.imsv.unibe.ch/research/talks/colloquia/index_eng.html">Colloquia on Probability and Statistics </a></div><br /><div class="event_speaker">Dr. Markus Tempelmayr (EPFL)</div><div class="event_title"><a class="external" href="https://www.imsv.unibe.ch/research/talks/schedule/index_eng.html">Weak universality of reaction-diffusion models with long-range correlated noise</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Reaction-diffusion equations are ubiquitous in mathematical descriptions of physical phenomena. In this talk, we show how long-range correlated noise in a microscopic model leads to a universal macroscopic behaviour. The macroscopic limit is reminiscent of the dynamical $\\Phi^4$ model, a singular stochastic PDE which is in need of renormalization. We shall see how details of the microscopic reaction term have a non-trivial effect on the coupling constant of the macroscopic limit, and how renormalization of the macroscopic equation has a harmless interpretation on the microscopic counterpart. Time permitting we give an idea of the proof, which is based on a term-by-term expansion (i.e. regularity structures) tailored to the law of the noise.</div><div class="event_time">16:15 &bull; Universität Bern, Hörsaal B78, ExWi, Sidlerstrasse 5, 3012 Bern</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. Luis Vega González (Basque Center for Appl. Math., Spain)</div><div class="event_title">The dynamics of viscous vortex filaments and the Binormal Curvature Flow <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I’ll present some recent work about the connection of vortex filaments/tubes that move according to Navier Stokes Equation and the binormal curvature flow of curves in 3d. This is a joint work with Marco A. Fontelos and Mikel Ispizua.</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">Dr. Benjamin Bonnefont (Université de Genève)</div><div class="event_title">Fourier dimension of imaginary Gaussian multiplicative chaos <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Recent works have established sharp Fourier decay for subcritical real Gaussian multiplicative chaos (GMC) on the circle, and in this talk I will discuss the corresponding harmonic picture for imaginary GMC. Gaussian multiplicative chaos is obtained by exponentiating log-correlated Gaussian fields; on the unit circle, one may take the trace of the two-dimensional Gaussian free field with covariance $\\log 1/|e^{i\\theta}-e^{i\\theta\'}|$. For purely imaginary parameters $\\gamma=i\\beta$ with $\\beta\\in(0,1)$, the resulting object $M_{i\\beta}$ exists as a complex-valued random distribution and enjoys strong integrability properties.The Fourier dimension captures the decay of the Fourier coefficients $c_n$ of a distribution. It is defined as the supremum of $s\\in(0,1)$ such that $|c_n|^2 = O(|n|^{-s})$. We prove that the Fourier dimension of $M_{i\\beta}$ is almost surely $1-\\beta^2$ and establish a joint CLT for the rescaled coefficients.The proof uses the method of moments specific to the imaginary regime. The moments of $c_n$ (and mixed moments of nearby modes) are rewritten as Coulomb-gas integrals on the circle, and then analysed via the Selberg inner product and Jack polynomial expansions, which convert the moment integrals into positive partition sums amenable to sharp asymptotic analysis.Joint work with Hermanni Rajamäki and Vincent Vargas.</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, March 19      </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"> Marino Gran (UCLouvain)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/epfl-topology-seminar-spring-2026/">Hopf formulas for cocommutative Hopf algebras</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In recent years, numerous new applications of categorical Galois theory have emerged in various interesting non-abelian algebraic contexts. In particular, within semi-abelian categories, this approach has led to some new calculations of higher fundamental groups in terms of generalized commutators in categories such as that of compact groups, crossed modules, and skew braces. These categories share some structural properties with the categories of groups and of Lie algebras, and also with the category of cocommutative Hopf algebras over a field, which is also semi-abelian.This raises the natural question of whether similar homological methods can be applied to study cocommutative Hopf algebras as well.In this talk, after reviewing some fundamental properties of semi-abelian categories and some motivating examples, I will explain that the answer to the above question is affirmative. By using the exactness properties of cocommutative Hopf algebras and the free functor universally associating a Hopf algebra with any coalgebra it is possible to establish some new Hopf-type formulae for the homology of cocommutative Hopf algebras. An important role is played by cleft extensions, namely those surjective morphisms of Hopf algebras that are split as coalgebra morphisms.With any cleft extension, one can associate a 5-term exact sequence in homology that can be seen as a Hopf-theoretic analogue of the classical Stallings-Stammbach exact sequence in group theory. This new approach can also be applied to investigate the homology of cocommutative Hopf braces, which are interesting structures that naturally occur in the study of solutions to the so-called quantum Yang-Baxter equation. The category of cocommutative Hopf braces turns out to be both semi-abelian and monadic on the category of coalgebras, so that it is possible to investigate it from the perspective of non-abelian homological algebra.This talk is based on a joint work with Andrea Sciandra.</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"> Shunhua  Jiang (ETH Zürich)</div><div class="event_title">Generalized Flow in Nearly-linear Time on Moderately Dense Graphs <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 consider generalized flow problems where there is an $m$-edge $n$-node directed graph $G = (V,E)$ and each edge $e \\in E$ has a loss factor $\\gamma_e >0$ governing whether the flow is increased or decreased as it crosses edge $e$. We provide a randomized $\\tilde{O}( (m + n^{1.5}) \\cdot \\mathrm{poly} \\log(\\frac{W}{\\delta}))$ time algorithm for generalized maximum flow and generalized minimum cost flow in this setting where $\\delta$ is the target accuracy and $W$ is the maximum of all costs, capacities, and loss factors and their inverses.This improves upon the previous state-of-the-art $\\tilde{O}(m \\sqrt{n} \\cdot \\log^2(\\frac{W}{\\delta}) )$ time algorithm, obtained by combining the algorithm of [Daitch-Spielman 2008] with techniques from [Lee-Sidford 2014].To obtain this result we provide new dynamic data structures and spectral results regarding the matrices associated to generalized flows and apply them through the interior point method framework of [Brand-Lee-Liu-Saranurak-Sidford-Song-Wang 2021]. Based on joint work with Michael Kapralov, Lawrence Li, and Aaron Sidford.</div><div class="event_time">11:15 &bull; EPF Lausanne, INJ114</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde">Bernoullis Tafelrunde</a></div><br /><div class="event_speaker"> Lucio Rosi (Universität Basel)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/studium/mathematik/doktorat/bernoullis-tafelrunde/detail/bernoullis-tafelrunde-lucio-rosi-basel/">Non-Uniqueness of Self-Similar Solutions for the Supercritical Complex Ginzburg-Landau Equation</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Abstract The Complex Ginzburg-Landau (CGL) equation is a fundamental nonlinear partial differential equation (PDE) frequently used to model a wide variety of evolution phenomena in a wide range of physical systems. It is also being studied as a model equation for other different nonlinear PDEs, like the incompressible Navier-Stokes equation in fluid dynamics. In this talk, we will present a numerical investigation into the existence, stability, and uniqueness of self-similar solutions to the CGL equation in the supercritical regime. The primary focus is on forward-in-time solutions in self-similar coordinates whose initial condition correspond to the blow-up profiles of backward-in-time self-similar solutions. The investigation seeks to determine whether the evolution of this forward profile from the singularity is unique.</div><div class="event_time">12:15 &bull; Universität Basel, Seminarraum 05.001, Spiegelgasse 5</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"> Killian Davis (Ohio State University)</div><div class="event_title">Nonadditivity of the Seifert Genus for Virtual Knots  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Classically, the Seifert genus for knots respects knot addition, leading to useful structural theorems, such as the fact that genus 1 knots are prime. For virtual knots, however, this is false. In this talk, we will demonstrate nonadditivity of the Seifert genus by showing two unknots which add to a genus 1 virtual knot. We will also introduce the main tool used to prove this: the homotopy Zh construction.</div><div class="event_time">14:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/forschung/mathematik/zahlentheorie/">Seminar Zahlentheorie</a></div><br /><div class="event_speaker"> Lucas Kaufmann (University of Orléans)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/number-theory-seminar-lucas-kaufmann/">Title T.B.A.</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Title: Equidistribution of periodic points for endomorphisms of P^k Abstract: Equidistribution phenomena are naturally present in several branches of mathemematics. The usual picture is that a sequence of points on a space X defined in some natural way always converge to a given limit distribution (a probability measure on X). In the case of dynamical systems, two natural choices are given by the iterated  pre-images of a given point or periodic points of period tending to infinity. In the holomorphic world,  it is known since the works of Lyubich in dimension 1 and Briend-Duval in any dimension that the periodic points of a holomorphic endomorphism of P^k equidisitribute towards its equilibrium measure.  Arithmetic versions also exist (Ullmo-Zhang,  Baker Rumely, Favre- Rivera-Letelier, Chamber-Loir, Yuan-Zhang, etc). In this talk, I will discuss  results concerning the speed of convergence in the above theorems in the holomorphic category. This is a joint work with H. de Thélin and T.-C. Dinh. Seminarraum 05.002, Spiegelgasse 5</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"> Emmanuel  Kowalski  (ETHZ)</div><div class="event_title">Bilinear forms with galant kernels <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Bilinear form structures occur frequently in analytic number theory, for instance in describing the primes. Estimating the norms of these bilinear forms is of crucial importance for applications.The talk will explain this general philosophy and present recent progress in the case of certain bilinear forms defined using kernels associated with "gallant" $\\ell$-adic sheaves.(Joint work with É. Fouvry, Ph. Michel and W. Sawin)</div><div class="event_time">14:15 &bull; EPF Lausanne</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://stat.ethz.ch/events/zukost">ZueKoSt: Seminar on Applied Statistics</a></div><br /><div class="event_speaker"> Jeffrey Näf (Université de Genève )</div><div class="event_title">Imputation under Missing at Random: How to Impute and How to Evaluate Imputations <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 take an in-depth look at the topic of missing value imputation. Focusing on the \'missing at random\' (MAR) case, we discuss the qualities that constitute an effective imputation method and how to evaluate them in practice. Crucially, we review common pitfalls in the literature that can bias subsequent analysis and explain how to avoid them, while also discussing some of the most promising imputation methods currently available. If time permits, we also briefly explore state-of-the-art research on evaluating an imputation method for a given dataset based on imputation scores (I-Scores).</div><div class="event_time">16:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Tom Hutchcroft (Caltech)</div><div class="event_title">Critical long-range percolation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />It is conjectured that many models of statistical mechanics have a rich, fractal-like behaviour at and near their points of phase transition, with power-law scaling governed by critical exponents that are expected to depend on the dimension but not on the small-scale details of the model such as the choice of lattice. This is now reasonably well understood in two dimensions and in high dimensions, but remains poorly understood in intermediate dimensions (e.g. d=3). I will overview the conjectures around this area and describe recent progress on related problems for models with long-range interactions.</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://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Prof. Dr. Hajer Bahouri (Laboratoire Jacques-Louis Lions, Sorbonne Université)</div><div class="event_title">On the global well-posedness the derivative nonlinear Schrödinger equation on the torus <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>In this talk, I will present a recent joint work with Galina Perelman concerning the derivative nonlinear Schr&ouml;dinger (DNLS) equation on the torus. The DNLS equation which is a canonical dispersive equation arising in a variety of physical contexts is known to be completely integrable (and then it admits a spectral formulation, an infinite number of conservation laws and explicit families of conservation laws). The main difficulty of this equation is the lack of coercivity of its conservation laws in the regime above the algebraic soliton threshold, and this makes large data global well-posedness a challenging issue. This equation was solved a short time ago on the real line, while &nbsp;the case of the torus is still less understood. In this work, we prove &nbsp;global well-posedness for DNLS equation on the torus.&lt;/p> &lt;p>The first part of my presentation will be devoted to a general overview of DNLS and completely integrable equations, then I will on the case of the torus &nbsp;by providing the new arguments that enabled us to achieve our goal.&nbsp;&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">Prof. Dr. Christian Bayer (WIAS Berlin)</div><div class="event_title">Markovian approximations of rough volatility models <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The rough Heston model is a very popular recent model in mathematical finance; however, the lack of Markov and semimartingale properties poses significant challenges in both theory and practice. A way to resolve this problem is to use Markovian approximations of the model. Several previous works have shown that these approximations can be very accurate even when the number of additional factors is very low. Existing error analysis is largely based on the strong error, corresponding to the L2 distance between the kernels. Extending earlier results by [Abi Jaber and El Euch, SIAM Journal on Financial Mathematics 10(2):309--349, 2019], we show that the weak error of the Markovian approximations can be bounded using the L1-error in the kernel approximation for general classes of payoff functions for European style options. Moreover, we give specific Markovian approximations which converge super-polynomially in the number of dimensions, and illustrate their numerical superiority in option pricing compared to previously existing approximations. The new approximations also work for the hyper-rough case H>&#8722;1/2. In addition, we provide explicit characterisations of the state space of the Markovian approximations. Joint work with Eduardo Ani Jaber and Simon Breneis.</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, March 20      </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_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_speaker">Dr. Danylo Radchenko (IHES)</div><div class="event_title">Multiple polylogarithms and the Steinberg module <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> I will talk about a surprising connection between the space of multiple polylogarithms on a d-dimensional algebraic torus, and the Steinberg representation of GL_d(Q). I will show how this leads to several new identities for multiple polylogarithms, implying, in paricular, that all polylogarithms can be expressed using polylogarithms of the form Li_{m,1,...,1}.The talk is based on a recent joint work with Steven Charlton and Daniil Rudenko.</div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/schools/sb/research/math/statistics-seminars/">Statistics Seminar </a></div><br /><div class="event_speaker"> Markus Reiss (Humboldt-Universität zu Berlin)</div><div class="event_title">Estimation for SPDEs from noisy observations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We consider stochastic evolution equations of the form dX(t)=A&#952;X(t)dt+BdWtwith a generator A&#952; on a Hilbert space, involving an unknown real or functional parameter &#952;. We consider observations dY(t)=X(t)dt+&#949;dVt, t&#8712;[0,T], in space-time white noise dV and ask about optimal estimation of &#952;. Minimax lower bounds reveal a rich picture, which we shall describe in detail for second-order elliptic operators A&#952;=&#8711;&#8901;(&#952;2&#8711;+&#952;1)+&#952;0. Optimal rates depend on the order of the coefficient &#952;i, the dimension and the asymptotics taken. An even richer structure appears for nonparametric estimation. The lower bound proofs rely on Hellinger bounds for cylindrical Gaussian measures and functional calculus for non-commuting, unbounded normal operators. A rate-optimal parametric estimator is obtained by a subtle preaveraging approach. Finally, a nonparametric diffusivity estimator and several open problems are presented.</div><div class="event_time">15:15 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Andrew Kresch (Universität Zürich)</div><div class="event_title">Specialization method and applications to rationality questions</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>';