var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-27"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-25"><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;">26.1 - 30.1.2026</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Winter Break 2025/26</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, January 26      </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/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Stefan  Haller (Universität Wien )</div><div class="event_title">Spectral invariants of the Rumin complex on contact manifolds and beyond <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />On a contact manifold, Rumin\'s complex provides a sequence of differential operators that is intrinsic to the contact structure and computes de~Rham cohomology. This is a Rockland complex, the analogue of an elliptic complex in the Heisenberg calculus. Subelliptic analysis permits to define and study associated spectral invariants. In particular, the analytic torsion and the eta invariant of Rumin\'s contact complex have been compared to Riemannian an CR-invariants by Biquard-Herzlich-Rumin, Rumin-Seshadri, and Albin-Quan.While Rumin\'s complex can be defined for a broad class of filtered (Carnot) manifolds, one 5-dimensional geometry stands out because its Rumin complex is as well behaved as the contact analogue. This geometry is determined by a generic rank two distribution (i.e. 2-plane field) in dimension five, a.k.a. (2,3,5) distribution. Equivalently, it can be characterized as a particular Cartan geometry associated with the exceptional Lie group G2. In this talk we will recall the contact case and discuss recent results on the analytic torsion and the eta invariant of (2,3,5) distributions.</div><div class="event_time">16:00 &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">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"> Alexandre Bestandji (EPFL)</div><div class="event_title"><a class="external" href="https://www.epfl.ch/labs/hessbellwald-lab/topology-seminar-fall-2025/">Information topology through topos cohomology</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />An observer describes a system by collecting data from many local points of observation whose domains can be coherently glued together. A Grothendieck topos formalizes this process through a site of observation points and their relations. In this view, a topos is a space of phenomena where empirical data are relationally structured. The cohomology of these sheaves measures obstructions to forming coherent global descriptions or finer incompatibilities between different descriptions.In their 2015 article The Homological Nature of Entropy, Pierre Baudot and Daniel Bennequin use cohomological tools from topos theory to reinterpret Shannon entropy. A system is modeled as a ringed site of experiments that partially or fully partition its space of possible states. On this site, a sheaf of modules encodes all conceivable measures of probabilistic information derived from these experiments, with each experiment acting on the sheaf to determine how information changes.The cohomology of this sheaf captures how well these information measures satisfy desirable properties under observation, interpreting entropy as a generator of first-degree cohomology and extending information measures to higher dimensions.In this talk, I will detail three cases of probabilistic information cohomology : classical, quantum and dynamical. You can find more materials here.</div><div class="event_time">16:00 &bull; <a class="external" href="https://plan.epfl.ch/?room==CM%201%20517">EPFL Lausanne</a></div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, January 27      </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/seminaire-danalyse-numerique">Séminaire d\'Analyse Numérique </a></div><br /><div class="event_speaker"> Konstantinos C.  Zygalakis (Edinburgh)</div><div class="event_title">Optimization (sampling) algorithms and (stochastic) differential equations: Theory and Insights <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The ability of calculating the minimum (maximum) of a function lies in the heart of many applied mathematics applications. In this talk, we will connect such optimization problems to the large time behaviour of solutions to differential equations. We will then establish (a control theoretic) frame-work that allow us to deduce their long-time properties as well as deducing the long-time properties of their numerical discretisations. Using this framework, we give an alternative explanation for the good properties of Nesterov method for strongly convex functions, as well as highlight the reasons behind the failure of the heavy ball method. If there is time we will discuss how to generalise these ideas in a non-Euclidean setting as well as how to extend this framework to study the non-asymptotic behaviour of the numerical solutions of stochastic differential equations.</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"> Aliaksandra  Novik  (Imperial College)</div><div class="event_title">Derived category of coherent systems on curves and its stability conditions <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Bridgeland stability conditions on derived categories have become a powerful tool for extracting geometric information about an underlying variety via wall-crossing phenomena. For a smooth irreducible complex projective curve C of genus greater than 0, Macrì showed that the space of stability conditions on D^b(C) is trivial up to the action of the universal covering of GL&#8314;(2, R). As a result, there is no room to deform stability conditions and apply wall-crossing.In this talk, we present one way to resolve this issue by enlarging the category from coherent sheaves on a curve to coherent systems. We introduce the derived category of coherent systems, describe an open subset of its stability manifold, and show that it detects the Brill–Noether theory of the underlying curve. This is based on joint work with Soheyla Feyzbakhsh.</div><div class="event_time">14:00 &bull; EPF Lausanne, CM 1 517</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, January 28      </div>      <div class="day_content">        <div class="day_content_item no_event">        No events scheduled today!        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, January 29      </div>      <div class="day_content">        <div class="day_content_item no_event">        No events scheduled today!        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, January 30      </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>';