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. 2</span>      <span style="float: right; text-align:right; width: 250px;">22.9 - 26.9.2025</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Autumn Semester 2025</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, September 22      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/fim/activities/nachdiplom-lectures">Nachdiplomvorlesung</a></div><br /><div class="event_speaker"> Eugenia Malinnikova (Stanford University)</div><div class="event_title">Carleman estimates, unique continuation, and Landis conjecture</div><div class="event_time">13:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://calendar.google.com/calendar/embed?mode=AGENDA&height=600&wkst=2&bgcolor=%23FFFFFF&src=t36it03v52cus2detrvinlgk18%40group.calendar.google.com&color=%235F6B02&ctz=Europe%2FZurich">Groups, Arithmetic and Algebraic Geometry Seminar </a></div><br /><div class="event_speaker"> Valerio  Toledano Laredo  (Northeastern University)</div><div class="event_title">Stokes phenomena, quantum groups and Poisson-Lie groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Quantum groups have long been known to be related to Conformal Field Theory through the Knizhnik-Zamolodchikov (KZ) equations. I will explain a more recent version of this construction which relies on the dynamical  KZ (DKZ) equations. Unlike their precursors, these have irregular singularities. The corresponding Stokes matrices, which encode the discontinuous change of asymptotics of solutions near singular points then turn out to be the R-matrices of the quantum group. In a parallel development, Boalch constructed the Poisson structure on the dual $G*$ of a complex reductive group $G$ by using Stokes phenomena for the simplest irregular connection on the trivial $G$-bundle over $\\mathbb{P}^1$. I will briefly review Boalch’s construction, and show that it can be obtained as a semiclassical limit of the construction of quantum groups from the DKZ equations. </div><div class="event_time">13:15 &bull; EPF Lausanne</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> Michael  Tagaris (LAPTh, Annecy)</div><div class="event_title">CS-Duality, RT Construction and Observables in U(1)^n Chern-Simons Theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&#921;n this talk, I will address the problem of defining and computing the U(1)^n Chern–Simons (CS) partition function on closed, oriented 3-manifolds in a fully gauge-invariant framework. In contrast to usual approaches, we do not gauge fix. Instead, using the tools of Deligne–Beilinson cohomology,  which naturally incorporates both differential and topological data, we work on the gauge classes of connections. By applying the reciprocity formulas of Deloup and Turaev, I will establish the so-called CS duality and demonstrate its relation to a Reshetikhin–Turaev topological invariant. Finally, I define Wilson loop observables within this framework and compute their expectation values, completing a fully consistent treatment of the theory in the closed manifold case.</div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 25</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Richard  Hind (University of Notre Dame)</div><div class="event_title">Lagrangian intersections and symplectic embeddings <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We prove an intersection result between Lagrangian tori inside the 4 dimensional cylinder and certain codimension 1 hypersurfaces with Lagrangian torus boundary. Intersections between polydisks and the hypersurfaces are also obtained, under weaker conditions. Consequences are computations of various shape type invariants, which result in symplectic embedding obstructions. There is a lot of rigidity, provided the domain is not \'thin\' relative to the target. This is joint work with Ely Kerman.</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_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. Roberto Monti (University of Padova)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Recent Results on 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 />I will present some recent results concerning the regularity problem for sub-Riemannian length-minimizing curves.In particular, I will discuss the first example of a non-smooth geodesic, which disproves a long-standing conjecture. These findings are part of a research project carried out in collaboration with several co-authors, including Alessandro Socionovo and others.</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, September 23      </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"> Sokratis Zikas (IMPA)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-sokratis-zikas-impa-1/">Cremona maps from (11,10) curves</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk I will present birational maps obtained by blowing up smooth space curves of genus 11 and degree 10. We will completely characterize the loci in the Hilbert scheme $H_{g,d}^S$ where the geometry of the birational map changes. We will also examine how varying the curve in $H_{g,d}^S$ affects the rigidity of the corresponding birational map, in the sense of rank 3 fibrations.</div><div class="event_time">10:30 &bull; Universität Basel, Seminarraum 00.003, Spiegelgasse 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/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Ivan  Mitrofanov (Université de Genève)</div><div class="event_title">Diameters of Følner sets <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />For a finitely generated amenable group, the isodiametric function Isodiam(n) is defined as the minimal diameter of a subset whose boundary-to-volume ratio is at most 1/n. We will discuss its relation to the asymptotic dimension control function and, in particular, show that amenable groups of finite Assouad–Nagata dimension satisfy Shalom’s property. In addition, we compute the asymptotic behavior of these functions for several classes of groups and demonstrate that Isodiam(n) can grow asymptotically faster than the logarithm of the Følner function, thus addressing a question of Nowak.The talk is based on joint work with Anna Erschler.</div><div class="event_time">10:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://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"> Eva Miranda (Universitat Politècnica de Catalunya)</div><div class="event_title">Singular Symplectic Manifolds</div><div class="event_time">13:15 &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/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Dr. Benedikt Gräßle   (Universität Zürich, Switzerland)</div><div class="event_title">Stable skeleton integral equations for general-coefficient Helmholtz transmission problems <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Variational formulations of layer potentials and boundary integral operators generalize their classical construction based on Green\'s functions. Unlike classical approaches, our method applies even when Green\'s functions are not explicitly available, such as for Helmholtz problems with rough (e.g., piecewise Lipschitz) coefficients. Wave-number explicit estimates and properties like jump conditions are obtained directly from variational principles. From this, we obtain a generalised Calderón identity and derivenonlocal (integral) formulation of acoustic transmission problems in heterogeneous media. The well-posedness of the resulting boundary integral equations is directly inherited from the underlying partial differential equation. Our analytical framework treats general spatial dimensions and complex wave numbers simultaneously by imposing an artificial boundary and employing recent insights into the associated Dirichlet-to-Neumann map.</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/seminaires/lie-sem/">Lie groups and moduli spaces </a></div><br /><div class="event_speaker"> Vladimir Fock (Strasbourg)</div><div class="event_title">Hecke algebras, TQFT and HOMFLY <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will discuss two applications of Iwahori-Hecke algebras. In the first one we construct a two-dimensional topological quantum field theory, which gives a q-generalization of Hurwitz numbers. However, the combinatorial meaning of these q-numbers remains unclear. The second construction exploits the connection between Hecke algebras and HOMFLY knot polynomials allowing computations in quantum groups and Hecke algebras representation theory using skein relations.</div><div class="event_time">15:30 &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/zurich-colloquium-in-mathematics">Zurich Colloquium in Mathematics</a></div><br /><div class="event_speaker"> Rob Morris (Instituto de Matemàtica Pura e Aplicada)</div><div class="event_title">An exponential improvement for diagonal Ramsey <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Ramsey number R(k) is the minimum n such that every red-blue colouring of the edges of the complete graph on n vertices contains a monochromatic copy of K_k. It has been known since the work of Erdos and Szekeres in 1935, and Erdos in 1947, that 2^{k/2} &lt; R(k) &lt; 4^k, but until recently the only improvements were by lower order terms. In this talk I will give an introduction to the area, and also sketch the proof of a recent result, which improves the upper bound of Erdos and Szekeres by a (small) exponential factor.Based on joint work with Marcelo Campos, Simon Griffiths and Julian Sahasrabudhe.</div><div class="event_time">16:30 &bull; ETH Zentrum, Building KO2, Room F 150</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, September 24      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Waltraud Lederle (TU Dresden)</div><div class="event_title">Elementwise conservative actions and boomerang subgroups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>We propose to study actions of countable groups on measure spaces such that every group element individually acts as a conservative transformation, that is, a transformation such that no set of positive measure is disjoint from all its translates. We construct such actions of the free group, using the measurable full group of a hyperfinite equivalence relation. The motivation for our work was to find interesting examples of boomerang subgroups.<br />Based on joint work with Y. Glasner and T. Hartnick.&lt;/p></div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Dr. Alessio Cela (Cambridge University)</div><div class="event_title">Pseudo-holomorphic curves with a fixed complex structure in positive symplectic manifolds <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, I will show that fixed-domain Gromov–Witten invariants of a positive symplectic manifold (e.g., a smooth Fano variety) are signed counts of J-holomorphic curves in X satisfying prescribed incidence conditions. This provides a symplectic analogue of a conjecture of Lian and Pandharipande, recently disproved in the algebraic setting by Beheshti, Lehmann, Lian, Riedl, Starr, and Tanimoto. The proof relies on constructing the fixed-domain Gromov–Witten pseudocycle without the use of inhomogeneous or domain-dependent perturbations, answering an old question posed by Ruan and Tian.</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Thomas Haettel (University of Montpellier)</div><div class="event_title">Nonpositively curved simplicial complexes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will present injective metric spaces, which are metric spaces where any family of pairwise intersecting balls has a non-empty global intersection. We will explain how they can be used to develop a rich theory of nonpositively curved simplicial complexes, somewhat parallel to the theory of CAT(0) cube complexes. We will show that they arise naturally for numerous spaces and groups: hyperbolic groups, buildings, braid groups, Artin groups, Garside groups, some arc complexes on surfaces... </div><div class="event_time">15:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/sam/news-and-events/zhacm-colloquia">Zurich Colloquium in Applied and Computational Mathematics</a></div><br /><div class="event_speaker">Prof. Dr. Haizhao Yang (University of Maryland)</div><div class="event_title">Modeling and Computation in the Space of Language: Symbolic and LLM-Based Approaches  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Scientific modeling and computation traditionally rely on structured mathematics and hand-designed algorithms. In this talk, I propose a new perspective: treating both modeling and computation as processes operating within the space of natural language. I will introduce two complementary approaches that realize this vision. The first uses symbolic learning based on tree structures to generate mathematical expressions, where modeling is performed by constructing symbolic trees and computation is governed by operator rules. The Finite Expression Method (FEX) exemplifies this approach by discovering interpretable, high-accuracy solutions to PDEs and physical systems. The second approach employs large language models (LLMs) for automatic code generation and reasoning to translate scientific problem descriptions into formal mathematical models and executable solvers to solve these problems. As an example, the OptimAI framework demonstrates how multi-agent LLM collaboration enables reliable end-to-end optimization problem modeling and solving. Together, these methods point toward a unified paradigm where symbolic and language models form the foundation for interpretable, scalable scientific discovery and computation</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>    </div>    <div class="day">      <div class="day_title">        Thursday, September 25      </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"> Bo\'az Klartag (The Weizmann Institute of Science)</div><div class="event_title">Isoperimetric inequalities in high-dimensional convex sets</div><div class="event_time">10:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://calendar.google.com/calendar/embed?mode=AGENDA&height=600&wkst=2&bgcolor=%23FFFFFF&src=t36it03v52cus2detrvinlgk18%40group.calendar.google.com&color=%235F6B02&ctz=Europe%2FZurich">Groups, Arithmetic and Algebraic Geometry Seminar </a></div><br /><div class="event_speaker"> Sokratis Zikas</div><div class="event_title">Automorphisms of smooth hypersurfaces and Gizatullin\'s problem <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let $X_d \\subset \\mathbb{P}^{n+1}$ be a smooth hypersurface of degree d. Classical theorems of Matsumura-Monsky and Chang state that every automorphism of $X_d$ is the restriction of a linear automorphism of the ambient space, except in the two exceptional cases (n,d) = (1,3) and (2,4). Nonetheless, when (n,d) = (1,3), every automorphism of $X_3$ can be realized as the restriction of a birational map of $\\mathbb{P}^{2}$.  Gizatullin’s problem concerns the last open case, i.e. which automorphisms of a smooth quartic surface $X_4 \\subset \\mathbb{P}^{3}$ are restrictions of birational selfmaps of the ambient space.In this talk we will employ the machinery of log Calabi-Yau pairs, and more specifically that of the volume preserving Sarkisov program, to completely address Gizatullin’s problem for the general non-trivial case: smooth quartics of Picard rank 2. We will see that the answer can be either positive or negative, the dependence being on the existence of certain curves on the quartic. This is joint work with Carolina Araujo and Daniela Paiva.</div><div class="event_time">10:15 &bull; EPF Lausanne, CM 013</div>        </div>        <div class="day_content_item important"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Damian Osajda (Copenhagen / Wroclaw)</div><div class="event_title">Drilling Hyperbolic Groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Drilling a closed hyperbolic 3-manifold along an embedded geodesic is a crucial technique in low-dimensional topology, transforming the fundamental group of the manifold into a relatively hyperbolic group. In this talk, we extend this concept by proving that, under appropriate conditions, a similar "drilling" operation can be applied to a (Gromov) hyperbolic group with the 2-sphere boundary.Our primary motivations and applications revolve around the Cannon Conjecture, which states that if the Gromov boundary of a hyperbolic group is homeomorphic to the 2-sphere, then the group is virtually (i.e., up to a finite-index subgroup) the fundamental group of a closed 3-manifold of constant negative curvature. We also explore the relatively hyperbolic counterpart—the Toral Relative Cannon Conjecture.Using drilling, we show that if the Toral Relative Cannon Conjecture holds, then the Cannon Conjecture is valid for all residually finite hyperbolic groups. The Toral Relative Cannon Conjecture appears more accessible, owing to the presence of additional structure—abelian parabolic subgroups.This is joint work with Daniel Groves, Peter Haïssinsky, Jason Manning, Alessandro Sisto, and Genevieve Walsh.</div><div class="event_time">13:00 &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_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"> Bruno  Cavalar</div><div class="event_title">Monotone circuit complexity of matching <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We show that the perfect matching function on $n$-vertex graphs requires monotone circuits of size $2^{n^{\\Omega(1)}}$. This improves on the $n^{\\Omega(\\log n)}$ lower bound of Razborov (1985). Our proof uses the standard approximation method together with a new sunflower lemma for matchings.</div><div class="event_time">14:00 &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/mpseminar/seminar.html">Séminaire de Mathématique Physique </a></div><br /><div class="event_speaker"> Hans  Jocker  (Uni Mainz)</div><div class="event_title">Wilson Loop Algebras and Quantum K-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 certain aspects of Wilson line operators in 3d N=2 supersymmetric gauge theories with a Higgs branch that is geometrically described by complex projective varieties. We discuss the relationship between Wilson loop algebras of the gauge theory and the quantum K-theoretic ring of the associated complex projective variety.</div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/seminar/epfl-topology-seminar-fall-2024/">Séminaire de Topologie </a></div><br /><div class="event_speaker"> Clemens Bannwart</div><div class="event_title">Tagged barcodes for Morse-Smale vector fields <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk I will present some new invariants for Morse-Smale vector fields. In the first part of the talk we consider the gradient-like case, where we construct an invariant called ‘tagged barcode’. We start by considering the Morse complex, which is a chain complex defined in terms of singular points and flow lines of the vector field and whose homology is isomorphic to the homology of the underlying manifold. We then identify a sequence of pairs of singular points along which we can simplify the Morse complex. Recording the distances between the pairs we simplified yields the tagged barcode. In the second part of the talk we include closed orbits into our analysis, presenting a different method where we use a filtration of the manifold by unstable manifolds first described by Smale. We consider the spectral sequence associated with this filtration and then rearrange the algebraic information in order to obtain a chain complex. This is joint work with Claudia Landi. The content of the first part can be found on arXiv (identifier 2401.08466), the content of the second part is work in progress.</div><div class="event_time">14:00 &bull; <a class="external" href="https://plan.epfl.ch/?room==CM%201%20517">EPF Lausanne, Mathematics</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://stat.ethz.ch/events/research_seminar">Research Seminar in Statistics</a></div><br /><div class="event_speaker"> Pragya Sur  (Harvard University)</div><div class="event_title">Data Integration: Challenges and Opportunities for Interpolation Learning under Distribution Shifts <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> Min-norm interpolators emerge naturally arise as implicit regularized limits of modern machine learning algorithms. Recently, their out-of-distribution risk was studied when test samples are unavailable during training. However, in many applications, a limited amount of test data is typically available during training. Properties of min-norm interpolation in this setting are not well understood. In this talk, I will present a characterization of the risk of pooled min-L2-norm interpolation under covariate and concept shifts. I will show that the pooled interpolator captures both early fusion and a form of intermediate fusion. Our results have several implications. For example, under concept shift, adding data always hurts prediction when the signal-to-noise ratio is low. However, for higher signal-to-noise ratios, transfer learning helps as long as the shift-to-signal ratio lies below a threshold that I will define. Our results also show that under covariate shift, if the source sample size is small relative to the dimension, heterogeneity between domains improves the risk. Time permitting, I will introduce a novel anisotropic local law that allows to achieve some of these characterizations and is of independent interest in random matrix theory. This is based on joint work with Kenny Gu, Yanke Song and Sohom Bhattacharya.</div><div class="event_time">15:00 &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_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/events/mathematics-colloquia/">Mathematics Colloquium </a></div><br /><div class="event_speaker"> Philippe  Rigollet (MIT)</div><div class="event_title">A Mathematical Perspective on Transformers <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Since their introduction in 2017, Transformers have revolutionized large language models and the broader field of deep learning. Central to this success is the groundbreaking self-attention mechanism. In this presentation, I’ll introduce a mathematical framework that casts this mechanism as a mean-field interacting particle system, revealing a desirable long-time clustering behavior. This perspective leads to a trove of fascinating questions with unexpected connections to Kuramoto oscillators, sphere packing, Wasserstein gradient flows, and slow dynamics.Please register on the following form : https://forms.gle/M5pYkYZ3uMqTLHqS9</div><div class="event_time">16:00 &bull; EPF Lausanne, CM 1 105</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/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Havva Yoldas (Delft Institute of Applied Mathematics)</div><div class="event_title">Deriving diffusion equations from nonlinear kinetic equations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>We will derive a class of nonlinear diffusion equations (covering both porous media and fast diffusion equations) as the hydrodynamic limit of a class of nonlinear, spatially inhomogeneous kinetic equations of BGK-type. These equations share the same superlinearity as the Boltzmann equation and fall into the class of run and tumble equations appearing in mathematical biology. We will look at the Cauchy problem under the parabolic scaling and also provide a quantitative nonlinear hypocoercivity result. The derivation is based on both the hypocoercivity and relative entropy methods. The talk is based on a joint work with Daniel Morris (TU Delft) and Josephine Evans (University of Warwick).&lt;/p></div><div class="event_time">16:00 &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_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"> Maxim Kontsevich (IHES Paris)</div><div class="event_title">Fractional dimensions of critical loci <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />With a critical locus of a holomorphic function, one can associate a certain rational number that can be thought of as a "dimension." This dimension can be determined in different ways: via analysis, Hodge theory, or triangulated categories. Singularities with a dimension less than one are precisely the isolated simple ones classified by Arnold, which correspond to the simply laced Dynkin diagrams</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://stat.ethz.ch/events/zukost">ZueKoSt: Seminar on Applied Statistics</a></div><br /><div class="event_speaker"> Sonja  Greven (Humboldt-Universität zu Berlin)</div><div class="event_title">Additive Density Regression <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We present structured additive regression models to model probability density functions given scalar covariates. To preserve nonnegativity and integration to one, we formulate our models for densities in a Bayes Hilbert space with respect to an arbitrary finite measure. This enables us to not only consider continuous densities, but also, e.g., discrete densities (compositional data) or mixed densities. Mixed densities occur in our application motivated by research on gender identity norms and the distribution of the woman’s share in a couple’s total labor income, as the woman’s income share is a continuous variable having discrete point masses at zero and one for single-earner couples. We show how to handle the challenging case of mixed densities using an orthogonal decomposition. We discuss interpretation of effect functions in our model via odds-ratios. We consider two cases: First, where densities are observed and are directly used as responses. Second, when only individual scalar realizations of the conditional distributions are observed, but not the whole conditional densities, we use our additive regression approach to model the conditional density given covariates. We show approximate equivalence of the resulting Bayes space penalized likelihood to a certain penalized Poisson likelihood, facilitating estimation. We apply our framework to a motivating gender economic data set from the German Socio-Economic Panel Study (SOEP) to analyze the distribution of the woman’s share in a couple’s total labor income, given year, place of residence and age of the youngest child. Results show a more symmetric distribution in East German than in West German couples after German reunification and a smaller child penalty comparing couples with and without minor children. These West-East differences become smaller, but are persistent over time.</div><div class="event_time">16:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room D 7.2</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/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Hezekiah Grayer</div><div class="event_title">Radiative Vlasov-Maxwell equations <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: #000000; color: #000000; font-family: -webkit-standard; font-size: medium; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; display: inline !important; float: none;">In the radiative Vlasov-Maxwell equations, the Lorentz force is modified by the addition of radiation reaction forces. The radiation forces produce damping of particle energy but the forces are no longer divergence-free in momentum space, which has an effect of concentration to zero momentum. We prove unconditional global regularity of solutions for a class of radiative Vlasov-Maxwell equations with large initial data. This is joint work with Peter&nbsp;Constantin.&lt;/span>&lt;/p></div><div class="event_time">17:00 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, September 26      </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"> Sascha Desmettre (University of Linz)</div><div class="event_title">Equilibrium Investment with Random and State-Dependent Risk Aversion <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We solve the problem of an investor who maximizes utility but faces random preferences. We propose a problem formulation based on expected certainty equivalents. We tackle the time-consistency issues arising from that formulation by applying the equilibrium theory approach. To this end, we provide the proper definitions and prove a rigorous verification theorem. We complete the calculations for the cases of power and exponential utility. For power utility, we illustrate in a numerical example, that the equilibrium stock proportion is independent of wealth, but decreasing in time, which we also supplement by a theoretical discussion. For exponential utility, the usual constant absolute risk aversion is replaced by its expectation. If time permits, we also elaborate on what happens when the risk aversion is driven by a factor process, and thus the investor can learn from former decisions.</div><div class="event_time">14:00 &bull; EPF Lausanne, Extranef 126</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"> Paolo Ventura (EPFL- AMCV)</div><div class="event_title">Long-wave instability of periodic shear flows for the 2D Navier-Stokes equations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will present a recent result regarding the long-wave instability of general shear flows. Under the sole condition that the H^{-1} norm of the steady velocity profile exceeds the kinematic viscosity, we are able to prove the onset of unstable spectrum for the linearized Navier-Stokes equations.This instability mechanism is derived through two independent approaches: a spectrum-oriented adaptation of Kato perturbative techniques and a conjugation-oriented normal-form reduction. Unlike in many other applications of these methods, both proofs deal with the presence of a peculiar term in the linearized operator that is singular with respect to the long-wave parameter. This work was carried out in joint collaboration with Maria Colombo, Michele Dolce and Riccardo Montalto.</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">Dr. Calla Tschanz (Ruhr Universität Bochum)</div><div class="event_title">From logarithmic Hilbert schemes to degenerations of hyperkähler varieties <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In this talk, I will discuss my previous work on constructing explicit models of logarithmic Hilbert schemes. This relates to work or Li-Wu on expanded degenerations, Gulbrandsen-Halle-Hulek on degenerations of Hilbert schemes of points and Maulik-Ranganathan on logarithmic Hilbert schemes. The constructions I consider are local. I will then explain how we globalise these in joint work with Shafi and apply them to construct minimal type III degenerations of hyperkähler varieties, namely Hilbert schemes of points on K3 surfaces.</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>';