var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-4"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-2"><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. 15</span>      <span style="float: right; text-align:right; width: 250px;">26.5 - 30.5.2025</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Spring Semester 2025</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, May 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"> Friedrich  Pukelsheim  (University of Augsburg, Germany)</div><div class="event_title">Fair representation of geographical districts and political parties: Double proportionality <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Recently several Cantons have adopted a double proportional representation system for the election of their cantonal parliament.  The speaker played a key role in the world première of the novel system in Zurich in 2006.  The lecture explains how this changeover came about, and which properties distinguish double proportionality in general.</div><div class="event_time">11:00 &bull; EPF Lausanne, Extranef 125</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">Dr. Francesco Morabito (ETH Z&uuml;rich, Switzerland)</div><div class="event_title">Braids and Morse/Floer complexes <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 focus our attention on compactly supported Hamiltonian diffeomorphisms of the plane. To each pair of distinct fixed points we can associate an integer, the linking number of the pair.Moreover, we can describe the dynamics of the diffeomorphism itself viathe Morse complex of a generating function. This Morse complex isclassically known to be filtered by action. In this talk we are going to show how we can equip its tensor power with a secondary filtrationwhich keeps track of the linking numbers of pairs of orbits. The proofrelies on foundational work on twist maps carried out by Patrice LeCalvez in the \'90s, and on uniqueness properties of generatingfunctions. Moreover, we are going to explain how using this language one may provide a finite-dimensional proof of Hofer-lower semicontinuity of the  topological entropy, first proved by Alves and Meiwes. One can define a similar filtration on Floer complexes using intersection products of pseudo-holomorphic cylinders as defined by Siefring: if time permits, we are going to provide a sketch of this construction.</div><div class="event_time">14:00 &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/symplectic-geometry-seminar">Symplectic Geometry Seminar</a></div><br /><div class="event_speaker"> Fabian Ziltener</div><div class="event_title">Instantaneous Hamiltonian displaceability and arbitrary symplectic squeezability for critically negligible sets <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This talk is about joint work with Yann Guggisberg.We call a metric space $s$-negligible iff its $s$-dimensional Hausdorff measure vanishes. We show that every countably $m$-rectifiable subset of $R^{2n}$ can be displaced from every $(2n-m)$-negligible subset by a Hamiltonian diffeomorphism that is arbitrarily $C^\\infty$-close to the identity. As a consequence, every countably $n$-rectifiable and $n$-negligible subset of $R^{2n}$ is arbitrarily symplectically squeezable. Both results are sharp w.r.t. the parameter $s$ in the $s$-negligibility assumption. </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"> Loren Coquille (Université de Grenoble Alpes)</div><div class="event_title">Delocalisation of the long-range Gaussian chain <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> will speak about the localisation/delocalisation properties of the discrete Gaussian chain with long-range interactions, which was the object of several conjectures since the nineties.In a first paper with van Enter, Le Ny and Ruszel, we cooked up a very short proof of the absence of shift-invariant Gibbs states at any temperature for any interaction decay power &#945;>2, which shows delocalisation of the chain in a non-quantitative manner.Later on, in a second paper with Dario and Le Ny, we obtained a quantitative version of this delocalisation.Combined with the results of Kjaer-Hilhorst, Fröhlich-Zegarlinski and Garban, our estimates provide an (almost) complete picture for the localisation/delocalisation of the discrete Gaussian chain. The proofs are based on graph surgery techniques which have been recently developed by van Engelenburg-Lis and Aizenman-Harel-Peled-Shapiro to study the phase transitions of two dimensional integer-valued height functions (and of their dual spin systems). </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. Andrea Agazzi (University of Bern)</div><div class="event_title"><a class="external" href="https://www.math.unibe.ch/research/talks/colloquium/index_eng.html">Clustering Dynamics in Mean-Field Models of Transformers</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Transformers are a central architecture in modern deep learning, forming the backbone of large language models such as ChatGPT. In this talk, I will present a mathematical framework for studying how information—represented as "tokens"—evolves through the layers of such neural networks. Specifically, we consider a family of partial differential equations that describe how the distribution of tokens—modeled as particles interacting in a mean-field way—changes with depth. Numerical experiments reveal that, under certain conditions, these dynamics exhibit a metastable clustering phenomenon, where tokens group into well-separated clusters that evolve slowly over time. A rigorous analysis of this behavior uncovers a range of open questions and unexpected connections to analysis and geometry.</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, May 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/groupes-geometrie">Groupes et Géométrie </a></div><br /><div class="event_speaker"> Alex Bishop</div><div class="event_title">On groups with EDT0L word problem <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />After demonstrating that the word problem of a group is solvable, one then wonders how difficult it is to describe the associated computation. A common method of categorising the complexity of sets of words is by their formal-language class, that is, the level of complexity required to present such a set. In this talk, we consider the groups whose word problems lie in the family of EDT0L languages. We note that EDT0L languages have recently become of great interest within group theory, in particular, as the solution to equations over hyperbolic groups, and as a method of presenting certain groups.Our main result is that if a group has an EDT0L word problem, then it must be torsion. This is a generalisation of a recent result which appeared in the PhD thesis of Paul Gallot. It is conjectured by Elder, Ciobanu and Ferov that a group has EDT0L word problem if and only if it is finite: this work is a step towards resolving this conjecture.This is a joint work with Murray Elder, Alex Evetts, Paul Gallot and Alex Levine.</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://www.epfl.ch/labs/mathicse/">Computational Science and Engineering </a></div><br /><div class="event_speaker"> Frédéric Schwander</div><div class="event_title">Application of Hybridizable Discontinuous Galerkin discretization for modelling of plasma transport in tokamaks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Power exhaust, particle and energy spatial distribution are key to the performance of tokamaks. Understanding the relation between these aspects and plasma properties, plasma scenario and plasma-facing components is instrumental in the design of optimized plasmas on the way to energy production through fusion.The laboratory M2P2 (Aix-Marseille Université, CNRS, Ecole Centrale Méditerranée), along with several collaborating research entities, is involved in the development of numerical tools towards the modelling of particle and energy circulation in the tokamak as well as heat flux on plasma-facing components through the 2D fluid transport code SolEdge-HDG. The latter is a steady-state solver, based on a high-order finite-element spatial discretization named Hybridizable Discontinuous Galerkin, in which the geometry of the wall is fully taken into account by adequate meshes that are constructed regardless of the magnetic field.The presentation will first bring a short introduction to Discontinuous Galerkin methods for the non-specialists, before moving to Hybridizable Discontinuous Galerkin methods, their working principle, distinctive features and perceived advantages. The presentation will then focus more in-depth on the code Soledge-HDG through a brief overview of the underlying physics, of the equations solved, general algorithm and workflow for a typical simulation. A final part will describe recent works, highlighting the capacity of the code to deal with time-varying magnetic fields and adaptive mesh refinement.</div><div class="event_time">11:00 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://calendar.google.com/calendar/embed?mode=AGENDA&height=600&wkst=2&bgcolor=%23FFFFFF&src=t36it03v52cus2detrvinlgk18%40group.calendar.google.com&color=%235F6B02&ctz=Europe%2FZurich">Groups, Arithmetic and Algebraic Geometry Seminar </a></div><br /><div class="event_speaker"> Sokratis Zikas (IMPA)</div><div class="event_title"> On Mori Dreamness of blowups along space curves <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Mori Dream Spaces are a special kind of varieties introduced by Hu and Keel that enjoy very good properties with respect to the Minimal Model Program. While Mori Dreamness is a very desirable property, it is not very well behaved with respect to even the simplest birational maps: blowups. In this talk we study Mori Dreamness of blowups along space curves: we provide various sufficient criteria as well obstructions to the blowup being a Mori Dream Space. We also study how this property behaves while varying the curve in the corresponding Hilbert scheme and show that it is neither an open nor a closed condition. Furthermore we exhibit examples of Hilbert schemes whose general element does not give rise to a Mori Dream Space, while special elements do, and vice versa.This is joint work in progress with Tiago Duarte Guerreiro.</div><div class="event_time">14:15 &bull; EPF Lausanne, CM 1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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. Björn Gebhard (Universität Münster)</div><div class="event_title">The Rayleigh-Taylor instability with local energy dissipation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We consider the inhomgeneous incompressible Euler equations describing two fluids with different constant densities under the influence of gravity. Initially the fluids are supposed to be at rest and separated by a flat horizontal interface with the heavier fluid being on top of the lighter one. Due to gravity this configuration is unstable, the two fluids begin to mix in a more and more turbulent way. This is one of the most classical instances of the Rayleigh-Taylor instability. In the talk we will see how weak locally dissipative solutions to the Euler equations reflecting a turbulent mixing of the two fluids in a quadratically growing zone can be constructed. If time allows, we will discuss an arising selection problem for the averaged motion of solutions.The core of the talk is based on a joint work with József Kolumbán.</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_fr"><a class="external" href="https://www.unifr.ch">Université de Fribourg</a></div><div class="event_type"><a class="external" href="https://sites.google.com/view/agms-fribourg-seminars/home">Seminar Analysis and geometry on metric spaces</a></div><br /><div class="event_speaker"> Yandi Wu (Rice University)</div><div class="event_title">Rigidity Phenomena for Surface Amalgams  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Geometric rigidity theory aims to determine the geometry of an object with the smallest amount of data possible. For instance, one could ask whether the volume or length set of a manifold determines its metric. In this talk, I will motivate and present some results related to length spectrum and volume rigidity for negatively curved surface amalgams, which are generalizations of negatively curved closed surfaces.</div><div class="event_time">15:15 &bull; Université de Fribourg, PER23 room 0.05</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"> Iva Halacheva  (Northeastern)</div><div class="event_title">An action of the Grothendieck-Teichmuller group on genus zero Kashiwara-Vergne solutions <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We identify genus zero Kashiwara–Vergne solutions which come from Drinfeld associators with moperad isomorphisms between the parenthesized braid and parenthesized chord diagram moperads. This extends the Alekseev–Enriquez–Torossian explicit construction of Kashiwara-Vergne solutions from Drinfeld associators, and provides explicit formulas for genus zero Kashiwara-Vergne solutions. Moreover, we show that our construction is a map of torsors, giving explicit descriptions of a free and transitive action of the Grothendieck–Teichmuller groups on genus zero KV solutions. This is joint work with Z. Dancso, G. Laplante-Anfossi, and M. Robertson.</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://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">Jana Göken (Kiel University)</div><div class="event_title">What is...a Torsionfree Lattice of Minimal Covolume in a Simpe Lie Group?</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, May 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"> Adam Kanigowski (University of Maryland)</div><div class="event_title">Sparse Equidistribution Problems in Dynamics</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"> Paolo Tomasini</div><div class="event_title">Equivariant elliptic cohomology from mapping stacks <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Equivariant elliptic cohomology is an equivariant cohomology theory associated to an elliptic curve. In this talk we will present a novel construction of complexified equivariant elliptic cohomology in an algebraic setting, in terms of functions over a stack of quasi-constant maps from an elliptic curve into a quotient stack. Based on joint work with Nicolò Sibilla.</div><div class="event_time">13:15 &bull; EPF Lausanne, CE 1 100</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">René Pfitscher (Université Sorbonne Paris Nord)</div><div class="event_title">Siegel transforms and counting rational approximations on flag varieties <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the divergence case of Khintchine\'s theorem, Schmidt established an asymptotic formula for the number of rational approximations of bounded height to almost every real number. Using tools from homogeneous dynamics and the geometry of numbers, we prove a version of this theorem for intrinsic Diophantine approximation on projective quadrics, Grassmannians, and other examples of flag varieties.</div><div class="event_time">13:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room F 5</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"> Lycka Drakengren (ETH Zürich)</div><div class="event_title"> The Chow ring of A_4 is... <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We outline a strategy for showing that the Chow ring of A_4 is tautological. The geometric setup involves a parametrization of the complement of the Jacobian locus by a moduli space of 6-nodal quartics in P^3. An ongoing collaboration with Sam Canning and Aitor Iribar-López.</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://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">Prof. Dr. Gianira Nicoletta Alfarano (Université de Rennes)</div><div class="event_title">The Geometry of One-Weight Linear Codes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A one-weight code, or constant-weight code, is an error-correcting code in which all codewords share the same weight. In 1984, Bonisoli provided a classification of one-weight linear codes by leveraging the connection between codes equipped with the Hamming metric and projective systems. More recently, similar geometric techniques have been applied to the study of linear codes in the rank metric. In this talk, we discuss one-weight linear rank-metric codes, by exploiting a new geometric framework. This is a joint work with Martino Borello and Alessandro Neri.</div><div class="event_time">15:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/geometry-seminar">Geometry Seminar</a></div><br /><div class="event_speaker"> Livio Liechti (Université de Fribourg)</div><div class="event_title">Pseudo-Anosov stretch factors of maximal algebraic degree <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In his seminal 1988 Bulletin article, Thurston showed that the stretch factor of a pseudo-Anosov map of a closed orientable surface is an algebraic integer of degree bounded from above by the dimension of the Teichmüller space of the surface. Thurston further claimed, without proof, that a construction of examples presented later in the article shows that this bound is sharp—a construction which nowadays is known as <i>Thurston’s construction</i> or <i>Thurston—Veech construction</i>. Margalit remarked in 2011 what Strenner wrote down in his 2017 article on algebraic degrees of stretch factors, namely that no proof of Thurston\'s claim has ever been published. In this talk, we present almost explicit examples of pseudo-Anosov maps obtained via the Thurston—Veech construction with stretch factors of maximal algebraic degree, finally substantiating Thurston\'s claim. This is joint work with Erwan Lanneau. </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_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_speaker"> Sasha Glazmann</div><div class="event_title">On percolation on planar graphs</div><div class="event_time">16:00 &bull; EPF Lausanne, CM1 517</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/forschung/mathematik/algebraische-geometrie/">Seminar Algebra and Geometry</a></div><br /><div class="event_speaker"> Fernando Figueroa (Northwestern University)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-algebra-and-geometry-fernando-figueroa-northwestern-university/">Calabi-Yau Pairs of Complexity Zero and Arbitrary Index</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Log Calabi-Yau Pairs are a generalization of Calabi-Yau varieties, naturally occurring when considering families or branched covers. The Complexity of a Calabi-Yau pair measures how far it is from being a toric pair. More concretely,  Brown, McKernan, Svaldi and Zong proved that any Calabi-Yau pair of index one and complexity 0 is a toric pair. Recent work of Mauri and Moraga has studied its crepant birational analogue, the "birational complexity", which measures how far the pair is from admitting a birational toric model. In this talk we will extend some of the previously known results for Calabi-Yau pairs of index one to arbitrary index. In particular we completely characterize Calabi-Yau pairs of complexity zero and arbitrary index. This is based on joint work with Joshua Enwright.</div><div class="event_time">16:00 &bull; Universität Basel, Seminarraum 00.003, Spiegelgasse 1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/aa/?events">Neuchatel - St.Gallen - Zurich Seminar in Coding Theory and Cryptography</a></div><br /><div class="event_speaker">Prof. Dr. Alessandro Neri (University of Naples Federico II)</div><div class="event_title">Ferrers Diagram Rank-Metric Codes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Ferrers diagram rank-metric codes were first studied in 2009 by Etzion and Silberstein, motivated by their application in network coding. Concretely, they arise from subspace codes entirely contained in a unique Schubert cell. In their work, the authors proposed a conjecture on the largest dimension of a linear space of matrices over a finite field whose nonzero elements are supported on a given Ferrers diagram and have all rank lower bounded by a fixed positive integer r. Since then, their conjecture has been proved only in some few cases, and as of today it still remains widely open. In this talk, I will give an overview of the main combinatorial and algebraic properties of Ferrers diagram rank-metric codes and on the state of art on the Etzion-Silberstein conjecture, starting from the first findings, until some very recent results.</div><div class="event_time">16:15 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://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"> Fael Rebei (ENS de Lyon)</div><div class="event_title">Exploration processes of the Brownian half-plane <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />This project is an ongoing work with Armand Riera. The Brownian half-plane is a random surface that arises as the universal scaling limit in the Gromov-Hausdorff sense of large graphs embedded in the closed half-plane. We will present two exploration processes of this surface; the horohulls and the hulls, which correspond roughly to exploring it from a point at infinity, and from its root. We characterize the law of the horohulls, which in turn provides information on the local topology of the half-plane. We describe the joint law of the horohulls and the hulls, and support the idea that they are dual processes. Then, we exhibit a simple martingale which is a function of the hulls, which allows to define another surface whose law is absolutely continuous to whose of the Brownian half-plane. We show that this surface exhibits hyperbolic features, with some links to 3D non random geometry. We end with a few conjectures/open questions.</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, May 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, May 30      </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"> Boris Bukh (Carnegie Mellon University)</div><div class="event_title">Discrete Geometry</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/algebraic-geometry-and-moduli-seminar">Algebraic Geometry and Moduli Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Sam Molcho (Sapienza Università di Roma)</div><div class="event_title">Poincaré sheaves, Fourier transform, and intersection theory on compactified Jacobians <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The weight decomposition and Fourier transform are among the most powerful tools in the study of intersection theory on an abelian scheme. In proper families abelian schemes tend to degenerate to certain singular objects -- semiabelic schemes or compactified abelian schemes for simplicity -- on which those tools are essentially lost. In this talk, I will discuss how to partially restore them in the case of certain families of compactified abelian schemes of central interest in the study of curves,  the compactified Jacobians, and how this leads to the determination of a large part of their tautological intersection theory. I will end by discussing some conjectures about weight decompositions on compactified Jacobians. This is joint work with Bae-Pixton. </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>';