var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-17"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-15"><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. 6</span>      <span style="float: right; text-align:right; width: 250px;">25.3 - 29.3.2024</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Spring Semester 2024</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, March 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/s/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> Vladimir Dotsenko (Université de Strasbourg)</div><div class="event_title">Lie algebra homology and wheeled operads <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I shall recall the definition of a wheeled operad (introduced by Merkulov about 15 years ago) and explain how homotopy invariants of wheeled operads appear naturally when computing stable homology of Lie algebras of derivations of free algebras. This a common generalization of the Loday-Quillen-Tsygan theorem on additive K-theory of an associative algebra, and the Fuchs\' stability theorem for homology of the Lie algebra of vector fields.</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://memento.epfl.ch/event/probability-and-stochastic-analysis-seminar/">Probability (and Stochastic Analysis) Seminar </a></div><br /><div class="event_title">Mini-workshop on Stochastic Dynamics and Stochastic Equations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The workshop will be held at the Bernoulli center, EPFL,  March 25 (Monday) -March 27 (Wed), 2024.  It is anticipated to start at 2pm on Monday and concludes 12:30 on Wednesday. The focus will be on SDEs, SPDEs, stochastic dynamics of stochastic equations, and related topics. </div><div class="event_time">14:00 &bull; EPF Lausanne, Bernoulli Center</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"> Jean-Philippe Chassé (ETH Zürich)</div><div class="event_title">The metric geometry of geometrically bounded Lagrangians <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />There are many natural metrics that one can put on the collection of all exact (closed connected) Lagrangians of a given Liouville manifold: Lagrangian Hofer metric, spectral metric, shadow metric, etc. However, in most instances, the known properties of the ensuing metric space are quite limited, as these spaces tend to be quite unruly. For this reason, I have previously studied the subspace of Lagrangians respecting an appropriate notion of "geometric boundedness"—a much more manageable space as it turns out. In this talk, I will present some new results on the metric properties in this smaller space of geometrically bounded Lagrangians, where all these metrics behave essentially the same. As applications, we will get some yet-unknown topological properties of the space of all exact Lagrangians of a Liouville manifold.</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"> Alessio Ranallo (UNIGE)</div><div class="event_title">Low energy spectrum of the XXZ model coupled to a magnetic field <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will report on recent developments concerning the control of a class of short-range perturbations of the Hamiltonian of an Ising chain. An example covered by our analysis is the celebrated XXZ chain. This is a joint work with S. Del Vecchio, J. Fröhlich, and A. Pizzo.</div><div class="event_time">16:15 &bull; Université de Genève, Conseil Général 7-9, Room 1-15</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_be"><a class="external" href="https://www.unibe.ch">Universität Bern</a></div><div class="event_type"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Mathematisches Kolloquium </a></div><br /><div class="event_speaker">Prof. Dr. Melanie Rupflin (Oxford University)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Quantitative estimates for geometric variational problems</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Many interesting geometric objects are characterised as minimisers or critical points of natural geometric quantities such as the length of a curve, the area of a surface or the energy of a map.For the corresponding partial differential equations and minimisation problems it is important to not only analyse the properties of exact solutions, but also to understand whether object that “almost solve the problem” provide good approximations of exact solutions.In particular, it is natural to ask whether a function whose energy is very close to the energy minimum must also essentially "look like" a minimiser, and if so whether this “stability of minimisers” holds in a quantitative sense, i.e. whether one can bound the distance of an almost minimiser to the closest minimiser in terms of the energy defect.In this talk we will discuss some of the ideas and challenges that appear in the study of this and related questions about the behaviour of almost solutions of PDE and variational problems. We will in particular consider the model problem of the classical Dirichlet energy of maps between spheres, where it has long been known that minimisers are given by meromorphic functions, but where the question of stability of minimisers has remained unclear until recently.</div><div class="event_time">17:15 &bull; Universität Bern, Sidlerstrasse 5, 3012 Bern, Lecture Room B6</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, March 26      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Hiroyasu  Izeki</div><div class="event_title">Harmonic maps and random walks on countable groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> Let Y be a proper CAT(0) space and G a countable group acting on Y. The main result of this talk says that if the action of G does not fix a point in the boundary at infinity of Y and its rate of escape is zero, then there is a flat subspace in Y left invariant by the action of G. The key ingredient of the proof is an equivariant harmonic map from G into Y.  Some consequences of this result will be also discussed.</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_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://memento.epfl.ch/event/probability-and-stochastic-analysis-seminar/">Probability (and Stochastic Analysis) Seminar </a></div><br /><div class="event_title">Mini-workshop on Stochastic Dynamics and Stochastic Equations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The workshop will be held at the Bernoulli center, EPFL,  March 25 (Monday) -March 27 (Wed), 2024.  It is anticipated to start at 2pm on Monday and concludes 12:30 on Wednesday. The focus will be on SDEs, SPDEs, stochastic dynamics of stochastic equations, and related topics. </div><div class="event_time">14:00 &bull; EPF Lausanne, Bernoulli Center</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ge"><a class="external" href="https://unige.ch">Université de Genève</a></div><div class="event_type"><a class="external" href="https://www.unige.ch/math/annonces/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Sebastien Loisel (Heriot-Watt University)</div><div class="event_title">Solving convex optimization problems in function spaces</div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 1-05</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://calendar.google.com/calendar/embed?mode=AGENDA&height=600&wkst=2&bgcolor=%23FFFFFF&src=t36it03v52cus2detrvinlgk18%40group.calendar.google.com&color=%235F6B02&ctz=Europe%2FZurich">Groups, Arithmetic and Algebraic Geometry Seminar </a></div><br /><div class="event_speaker"> Mitchell Taylor</div><div class="event_title">Stable phase retrieval in function spaces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />  Let $(\\Omega,\\Sigma,\\mu)$ be a measure space and $1\\leq p\\leq \\infty$. A subspace $E\\subseteq L_p(\\mu)$ is said to do \\emph{stable phase retrieval (SPR)} if there exists a constant $C\\geq 1$ such that for any $f,g\\in E$ we have     \\begin{equation}       \\inf_{|\\lambda|=1} \\|f-\\lambda g\\|\\leq C\\||f|-|g|\\|.    \\end{equation}    In this  case, if $|f|$ is known, then $f$ is uniquely determined up to an unavoidable global phase factor $\\lambda$; moreover, the phase recovery map is $C$-Lipschitz. Phase retrieval appears in several applied circumstances, ranging from crystallography to quantum mechanics.In this talk, I will present some elementary examples of subspaces of $L_p(\\mu)$ which do stable phase retrieval and discuss the structure of this class of subspaces. In particular, I will explain how SPR connects to $\\Lambda(p)$-set theory, which is a classical topic in the intersection of number theory and harmonic analysis. The material in this talk is based on joint work with M.~Christ and B.~Pineau as well as with D.~Freeman, T.~Oikhberg and B.~Pineau. </div><div class="event_time">14:15 &bull; EPF Lausanne, MA A1 10 </div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Anuj Kumar (UC Berkeley)</div><div class="event_title">Nonunique solutions of the transport equation for Sobolev vector fields <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We construct nonunique solutions of the transport equation in the class $L^\\infty$ in time and $L^r$ in space for divergence free Sobolev vector fields $W^{1, p}$. We achieve this by introducing two novel ideas: (1) In the construction, we interweave the scaled copies of the vector field itself. (2) Asynchronous translation of cubes, which makes the construction heterogeneous in space. These new ideas allow us to prove nonuniqueness in the range of exponents beyond what is available using the method of convex integration and sharply matchwith the range of uniqueness of solutions from Bruè, Colombo, De Lellis ’21.</div><div class="event_time">15:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/zurich-colloquium-in-mathematics">Zurich Colloquium in Mathematics</a></div><br /><div class="event_speaker"> Isabelle Gallagher</div><div class="event_title">On the dynamics of dilute gases <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Abstract: The evolution of a gas can be described by different models depending on the scale of observation. A natural question, raised by Hilbert in his sixth problem, is whether these models provide consistent predictions. On the one hand Lanford showed in 1974 that the Boltzmann equation appears as a law of large numbers in the low density limit of a gas of hard spheres, at least for very short times. On the other hand, fluid mechanics equations such as the Navier-Stokes equations can be derived from the Boltzmann equation in the limit of when the mean free path tends to zero. Reconciling both approaches in order to derive fluid mechanics equations from Newton\'s laws for the system of particles is to this day an open question.In this talk we shall explain these different limiting procedures, their difficulties and some recent advances in Hilbert\'s program.</div><div class="event_time">16:30 &bull; UZH Zentrum, Building KO2, Room F 150</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, March 27      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_fr"><a class="external" href="https://www.unifr.ch">Université de Fribourg</a></div><div class="event_type"><a class="external" href="https://commonweb.unifr.ch/_Science/Math/Pub/Math/seminars/OSgeom-top.html">Oberseminar Geometrie</a></div><br /><div class="event_speaker"> Menny Akka (ETHZ)</div><div class="event_title">Seifert surfaces, planes in four space, and Gauss composition <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Oberseminar GeometrieDepartment of MathematicsUniversity of FribourgPhysics 2.52Wednesday, 27 March 2024, 10:20Menny Akka (ETH Zürich)Seifert surfaces, planes in four space, and GausscompositionIn this talk I will present results from a recent joint work with PeterFeller, Alison Beth Miller and Andreas Wieser;https://arxiv.org/abs/2311.17746I will first present a geometric approach to the classical Gauss compo-sition of binary quadratic forms. The new method is based on a parame-terisation of two-dimensional subspaces of the space of 2x2 matrices andprovides an easy to remember way to compute the Gauss composition.This approach naturally leads to a robust construction of pairs ofSeifert surfaces for the same knot that are non-isotopic in the 4-ball.It also provides a complete characterisation of the Seifert forms of suchdisjoint Seifert surfaces. These topological results will be discussed inthe second part of the talk.Time permitting, I will sketch related equidistribution problems thatmotivated and are motivated by the above results.No background in number theory, knot theory or dynamical systems will be assumed.</div><div class="event_time">10:20 &bull; Université de Fribourg, room Phys 2.52</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Pedram Safaee (Universität Zürich)</div><div class="event_title">Nondegeneracy of the spectrum of the twisted Cocycle for interval exchange transformations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will introduce the concept of twisted Birkhoff sum and the twisted Cocycle. We give some motivations for studying this Cocycle and discuss the positivity of the top Lyapunov exponent. This is based on joint work with Hesam Rajabzadeh.</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_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://memento.epfl.ch/event/probability-and-stochastic-analysis-seminar/">Probability (and Stochastic Analysis) Seminar </a></div><br /><div class="event_title">Mini-workshop on Stochastic Dynamics and Stochastic Equations <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The workshop will be held at the Bernoulli center, EPFL,  March 25 (Monday) -March 27 (Wed), 2024.  It is anticipated to start at 2pm on Monday and concludes 12:30 on Wednesday. The focus will be on SDEs, SPDEs, stochastic dynamics of stochastic equations, and related topics. </div><div class="event_time">14:00 &bull; EPF Lausanne, Bernoulli Center</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"> Marcello Porta (SISSA)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-marcello-porta-sissa/">Dynamics of mean-field Fermi systems with nonzero pairing</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will discuss the dynamics of many-body Fermi gases, in the mean-field regime. I will consider a class of initial data which are close enough to quasi-free states, with a non-zero pairing matrix. Assuming a suitable semiclassical structure for the initial datum, expected to hold at low enough energy and that we can establish for translation-invariant states, I will present a theorem that shows that the many-body evolution of the system can be well approximated by the Hartree-Fock-Bogoliubov equation, a non-linear effective evolution equation describing the coupled dynamics of the reduced one-particle density matrix and of the pairing matrix. Joint work with Stefano Marcantoni (Nice) and Julien Sabin (Rennes).</div><div class="event_time">14:15 &bull; Universität Basel</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, March 28      </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"> Umut Çetin (London School of Economics)</div><div class="event_title">Mathematics of Market Microstructure</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://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. Marcin Napiórkowski (University of Warsaw)</div><div class="event_title">Beliaev damping in Bose gas <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />According to the Bogoliubov theory, the low energy behaviour of the Bose gas at zero temperature can be described by non-interacting bosonic quasiparticles called phonons. In my talk I will explain how the damping rate of phonons at low momenta, the so-called Beliaev damping, can be computed with simple arguments involving an effective Friedrichs model for phonons.</div><div class="event_time">16:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 46</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, March 29      </div>      <div class="day_content">        <div class="day_content_item no_event">        No events scheduled today!        </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>';