var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-34"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-32"><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. 11</span>      <span style="float: right; text-align:right; width: 250px;">27.11 - 1.12.2023</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Autumn Semester 2023</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, November 27      </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://math.ethz.ch/s/talks-in-mathematical-physics">Talks in Mathematical Physics</a></div><br /><div class="event_speaker"> Sebastian Schlegel Meija</div><div class="event_title">BPS Algebras and Generalised Kac-Moody algebras from 2-Calabi-Yau categories <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />https://www.math.uzh.ch/mat074</div><div class="event_time">13:15 &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://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">Prof. Dr. Sophie Grivaux (CNRS, Lille)</div><div class="event_title">Some new results regarding convergence under xqxp-invariant measures on the circle <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />For each integer n \\geq 1, denote by T_n the map x \\mapsto nx mod 1 from the circle group T=R/Z into itself. Let p,q \\geq 2 be two multiplicatively independent integers. Using Baire Category arguments, we will show that generically, a continuous T_p-invariant probability measure \\mu on T is such that (T_q^{n}\\mu)_{n\\geq 0} does not weak-star converge to the Lebesgue measure on T. This disproves Conjecture (C3) from a 1988 paper by R. Lyons, which is a stronger version of Furstenberg\'s rigidity conjecture on xp and xq invariant measures on T, and complements previous results by Johnson and Rudolph. If time permits, I will also present some generalizations of this result concerning convergence to the Lebesgue measure of sequences of the form (T_{c_{n}}\\mu)_{n\\geq 0}, as well as some extensions to the multidimensional setting. The talk will be based on a joint work with Catalin Badea (Lille).</div><div class="event_time">15:00 &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_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"> Christos Papadimitriou (Columbia University)</div><div class="event_title">How does the brain create language?  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />There is no doubt that all cognitive phenomena are the result of the activity of neurons and synapses, and yet there has been slow progress toward articulating a computational theory of how exactly this happens. I will introduce a simplified mathematical model of the brain, which we call NEMO, involving brain areas, spiking neurons, random synapses and weights, local inhibition, Hebbian plasticity, and long-range interneurons -- importantly, there is no back propagation in NEMO. Emergent behaviors of the resulting dynamical system -- established both analytically and through simulations -- include stable neural representations which we call assemblies, sequence memorization, one-shot learning, and universal computation. NEMO is also a software-based neuromorphic system that can be simulated efficiently at the scale of tens of millions of neurons, emulating certain high-level cognitive phenomena, such as parsing of natural language.  I will describe our recent implementation of a basic language acquisition system: a neural tabularasa which, on input consisting of a modest amount of grounded sentences in any natural language, is capable of learning a lexicon, syntax, semantics, comprehension, and generation in the same language (all terms will be defined). Finally, I will argue that experimenting with such brain-like devices, devoid of back propagation, besides providing insights into the way the brain works, can reveal novel and complementary avenues to learning, and may end up advancing AI.</div><div class="event_time">16:15 &bull; EPF Lausanne, BC 420</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, November 28      </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"> Claudio Llosa (Karlsruhe Institute of Technology)</div><div class="event_title">Finiteness properties of coabelian subgroups of hyperbolic groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Hyperbolic groups form an important class of finitely generated groups that has attracted much attention in Geometric Group Theory. We call a group of finiteness type $F_n$ if it has a classifying space with finitely many cells of dimension at most $n$, generalising finite generation and finite presentability, which are equivalent to types $F_1$ and $F_2$. Hyperbolic groups are of type $F_n$ for all $n$ and it is natural to ask if their subgroups inherit these strong finiteness properties. In recent work with Py, we used methods from Complex Geometry to prove that for every $n>0$ there is a hyperbolic group with a subgroup of type $F_{n-1}$ and not $F_n$. This answers an old question of Brady and produces many finitely presented non-hyperbolic subgroups of hyperbolic groups. In this talk we will explain this result and present other recent progress on constructing coabelian subgroups of hyperbolic groups with exotic finiteness properties. This talk is based on joint works with Kropholler, Martelli--Py, and Py.</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://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat770.1">Oberseminar: Algebraische Geometrie</a></div><br /><div class="event_speaker">Dr. Jean-Baptiste Teyssier (Université Sorbonne)</div><div class="event_title">Cohomological boundedness for flat bundles and applications <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We will advertise some consequences of the conjectural existence of moduli spaces for flat bundles with prescribed behaviour at infinity. We will then sketch unconditional proofs in the surface case. This is joint work with Haoyu Hu.</div><div class="event_time">13:15 &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_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"> Davide Perego (University of Sevilla)</div><div class="event_title">Finiteness properties of coabelian subgroups of hyperbolic groups <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The Gromov boundary of a hyperbolic group is a widely studied object in the field of geometric group theory. Many authors tried to provide topological approximations and recursive presentations for this boundary. After recalling some properties of hyperbolic groups and language theoretic notions, we will describe the tree of atoms. It was originally introduced by Belk, Bleak and Matucci in order to prove that hyperbolic groups embed into the rational group of asynchronous transducers and, later, to prove the Boone-Higman conjecture. Then, we will speak about its connections with the hyperbolic world and we will see some ways to approximate and recursively present the Gromov boundary via this tree.</div><div class="event_time">14:00 &bull; Université de Genève, Conseil Général 7-9, Room 6-13</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"> Nicola Guglielmi (GSSI L\'Aquilla)</div><div class="event_title">Solving numerically differential equations with distributed delays <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Sinopsis:In the early Nineties Ernst Hairer developed a famous code for the numerical approximation of stiff and differential algebraic problems, Radau5, which is based on the $3$-stage Radau IIa Runge Kutta method. The code became very popular and is nowadays one of the most important for the numerical approximation of implicit and stiff ODEs.Later, between 2000 and 2005, Ernst and I developed a code, Radar5, which extended Radau5 to delay differential equations with discrete delays (in short DDEs).Due to the increasing importance of models with distributed delays, for example in pharmacodynamics and pharmacokinetics (e.g Shuhua Hu et al., 2018), we have been recently addressed to certain kind of differential equations with distributed delays (in short DDDEs), where the dependence on the solution in the past appears through an integral term.In this talk I will explain how these problems can indeed be approximated by suitable systems of ODEs or DDEs, according to the kind of distributed term.The main ideas here are two:(i) replacing the kernels by suitable quasi-polynomial expansions, that is sums of polynomials multiplied by exponentials, and then transforming the distributed (integral) delay term into a set of ODEs (or DDEs);(ii) making the method efficient by exploiting the structure at the level of the linear algebra.Numerical evidence of the effectiveness of the proposed approach is illustrated on a few illustrative examples.</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_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/daco-seminar">DACO Seminar</a></div><br /><div class="event_speaker"><a class="external" href="https://www.iam.uni-bonn.de/users/brennecke/home">Prof. Dr. Christian Brennecke (University of Bonn )</a></div><div class="event_title">Operator Norm Bounds on the Correlation Matrix of the SK Model <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 review basic predictions for the high temperature regime, the so called replica symmetric regime, of the Sherrington-Kirkpatrick mean field spin glass. I will recall the TAP equations and their derivation in connection with the decay of the two point correlation functions. For the simplified case of vanishing external field, I will present some details on recent results that characterize the susceptibility of the model as a resolvent of the interaction matrix, which predicts in a simple way the (well-known) RS-RSB transition temperature. The talk is based on joint work with Adrien Schertzer, Changji Xu and Horng-Tzer Yau.</div><div class="event_time">14:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Stevan Gajovic (Charles University Prague)</div><div class="event_title">Title T.B.A.</div><div class="event_time">14:15 &bull; EPF Lausanne </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"> Giuseppe Carleo (EPFL)</div><div class="event_title">Title T.B.A.</div><div class="event_time">16:15 &bull; EPF Lausanne, GA 3 21</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"> Zohreh Ravanpak (Timisoara)</div><div class="event_title">Nonassociative generalization of Lie groupoids and discrete mechanics <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Smooth Loops are a generalization of Lie groups by dropping associativity.They are well-established objects in mathematics and they found severalapplications in physics and geometry. In this talk, we extend this notion tosmooth loopoids, nonassociative analogs of Lie groupoids.Lie groupoids play an important role in the standard formulation of discreteLagrangian and Hamiltonian Mechanics. After recalling this formalism in thesecond part of the talk, we show that the associativity assumption is notessential here. This is illustrated in an example using unitary octonions as thediscrete configuration space of a mechanical system.This is based on joint work with J. Grabowski.</div><div class="event_time">16:30 &bull; Université de Genève, Section de mathématiques, 7-9 rue du Conseil-Général, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ne"><a class="external" href="https://unine.ch">Université de Neuchâtel</a></div><div class="event_type"><a class="external" href="http://www.unine.ch/math/home/colloques_et_seminaires/les-colloques-du-mardi.html">Colloque du Mardi </a></div><br /><div class="event_speaker"> Peter Feller (ETHZ)</div><div class="event_title">Controlled hyperbolization of 3-manifolds <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />After a brief survey of the study of low-dimensional manifolds -- spaces locally modelled on the topological space R^n for n&lt;5 -- we will discuss the idea of geometrization. The latter refers to a program, initiated by Thurston, of studying 3-dimensional manifolds by means of eight geometric model spaces, which include the Euclidean space (R^3 endowed with the ordinary Euclidean metric) and hyperbolic space.It turns out that most 3-dimensional manifolds carry a hyperbolic structure, i.e. they are locally modelled on hyperbolic space. A precise version of this statement was proven by Maher invoking topological work of Hempel and Perelman\'s celebrated analysis results on Ricci-flow. We will discuss an approach to hyperbolization of most 3-dimensional manifolds that circumvents invoking the Ricci flow. As an upshot, with this approach one can control many geometric quantities such as injectivity radius, diameter, and volume of hyperbolic structures. We will provide ``hands-on\'\' examples of 3-manifolds that can be hyperbolized with this scheme.Based on joint work in progress with A. Sisto and G. Viaggi. No knowledge of low-dimensional topology or hyperbolic geometry will be assumed.</div><div class="event_time">17:00 &bull; Université de Neuchâtel, Institut de Mathématiques, B103</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/sfs/news-and-events/stiefel-lectures">ETH-FDS Stiefel Lectures</a></div><br /><div class="event_speaker"> Daniela M. Witten (University of Washington)</div><div class="event_title">Data thinning and its applications <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We propose data thinning, a new approach for splitting an observation from a known distributional family with unknown parameter(s) into two or more independent parts that sum to yield the original observation, and that follow the samedistribution as the original observation, up to a (known) scaling of a parameter. This proposal is very general, and can be applied to a broad class of distributions within the natural exponential family, including the Gaussian, Poisson,negative binomial, Gamma, and binomial distributions, among others. Furthermore, we generalize data thinning to enable splitting an observation into two or more parts that can be combined to yield the original observation using anoperation other than addition; this enables the application of data thinning far beyond the natural exponential family.Data thinning has a number of applications to model selection, evaluation, and inference. For instance, cross-validation via data thinning provides an attractive alternative to the "usual" approach of cross-validation via sample splitting,especially in unsupervised settings in which the latter is not applicable. We will present an application of data thinning to single-cell RNA-sequencing data, in a setting where sample splitting is not applicable.This is joint work with Anna Neufeld (Fred Hutch), Ameer Dharamshi (University of Washington), Lucy Gao (University of British Columbia), and Jacob Bien (University of Southern California)</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room F 30</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://www.unifr.ch/math/de/info/kolloquium.html">Colloquium </a></div><br /><div class="event_speaker"> Thomas Mettler (FernUni Schweiz)</div><div class="event_title">The Schwarzian derivative and the degree of a classical minimal surface <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The talk starts with a gentle introduction to minimal surfaces and basic notions from projective geometry. Using the Schwarzian derivative I will then explain how to construct a sequence of meromorphic differentials on every non-flat oriented minimal surface in Euclidean 3-space. A minimal surface is said to have degree n if its n-th differential is a polynomial expression in the differentials of lower degree. Various well-known minimal surfaces are identified as surfaces of low degree. Based on joint work with Jacob Bernstein & Lukas Poerschke. </div><div class="event_time">17:15 &bull; Université de Fribourg, room Phys 2.52</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Wednesday, November 29      </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"> Livio Liechti (Uni Fribourg)</div><div class="event_title">Asymptotically optimal multicurve intersection degrees <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Let M be an integer square matrix with at least one simple eigenvalue, and let N be its principal submatrix obtained by deleting the firstrow and the first column. We show that if the spectra of M and N aredisjoint, then there are infinitely many ways to change the top left coefficient of M so that its characteristic polynomial becomes irreducible.This criterion applies flawlessly to oscillatory matrices, but also to certain well-chosen classes of Perron-Frobenius matrices. In the second partof the talk, we will apply the criterion to describe the asymptotically optimal degrees of spectral radii of intersection matrices built from pairsof filling multicurves on closed orientable surfaces: the ratio betweenthe highest obtainable degree and the genus converges to 3 as the genustends to infinity. This is joint work with Erwan Lanneau.</div><div class="event_time">10:20 &bull; Université de Fribourg, 0.05 PER23</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"> Anders Karlsson (UNIGE)</div><div class="event_title">Metrics and a cut-off phenomenon in deep learning  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Today’s AI is based on neural networks and deep learning. These concepts are easily explained to a mathematician. Why and exactly how it works are however much more unclear, and the problems and risks associated with this are widely discussed. Products of random transformations occur in practice in several ways in deep learning (initialization, stochastic gradient descent, drop-out, etc). There is a noncommutative ergodic theorem that governs such products asymptotically. For less large neural networks we also found empirical evidence of a cut-off phenomenon for random initialization. Ongoing work with B. Avelin (Uppsala) and B. Dherin (Google).</div><div class="event_time">10:30 &bull; Université de Genève, Conseil Général 7-9, Room 1-07</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_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"> Sergio Simonella (University of Roma La Sapienza)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-analysis-and-mathematical-physics-sergio-simonella-university-of-roma-la-sapienza-1/">Boltzmann equation, hard sphere systems and their small and large deviations</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>https://nccr-swissmap.ch/news-and-events/news/next-kinetic-theory-seminar-29th-nov-prof-sergio-simonella-university-roma-la-sapienza&lt;/p></div><div class="event_time">13:45 &bull; Universität Basel, room 05.002 Department of Mathematics and Computer Science, Spiegelgasse 5, Basel.</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"> Harry Petyt (Oxford University, UK)</div><div class="event_title">Coarse obstructions to cubulation <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Given a group G, finding a geometric action of G on a CAT(0) cube complex can be used to say some rather strong things about G. Such actions are not always easy to find, however, which makes it useful to have sufficient conditions, both for existence and for non-existence. This talk concerns the latter: we shall see a coarse geometric obstruction to a group admitting a cocompact cubulation. Based on joint work with Zach Munro.</div><div class="event_time">15:45 &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"> Kevin Buzzard</div><div class="event_title"> Interactive theorem provers: can they help mathematicians? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />An interactive theorem prover is, amongst other things, a programming language which is sufficiently rich that it can in theory understand modern mathematical research. Two natural questions then arise. First, can these systems understand modern mathematical research _in practice_, and secondly, can they actually help us mathematicians to do it? For many years the answer to both questions was a resounding "no". But recently things have begun to change. There are several examples of recently-proved theorems which have been checked by Lean. Furthermore, interacting with these systems forces you to tidy up your ideas and think clearly about abstractions, which can have unexpected positive practical consequences. Also, modern systems are opening up new possibilities for teaching and communicating mathematics. I will give an overview of what has been going on recently in this area, suitable for mathematicians; no background from computer science will be assumed.</div><div class="event_time">16:00 &bull; EPF Lausanne, seminar room MED 0 1418</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. Daniel Freeman (Saint Louis University, USA)</div><div class="event_title">Vector recovery from saturated frame coefficients <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />A frame (x_j) for a Hilbert space H allows for a linear and stable reconstruction of any vector x in H from the linear measurements (&lt;x,x_j>).  However, there are many situations where some information of the frame coefficients is lost.   In applications such as signal processing, electrical engineering, and digital photography one often uses sensors with an effective range and any measurement above that range is registered as the maximum.  Depending on the context, recovering a vector from such measurements is called either declipping or saturation recovery. We will discuss a frame theoretic approach to this problem in a similar way to what Balan, Casazza, and Edidin did for phase retrieval.    This perspective motivates many interesting open problems.  The talk is based on joint work with W. Alharbi,  D. Ghoreishi, B. Johnson, and N. Randrianarivony.</div><div class="event_time">16:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room E 1.2</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, November 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"> Javier Fresán (Sorbonne Université)</div><div class="event_title">E-functions and 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_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"> Tommaso Botta (ETHZH)</div><div class="event_title">Bow varieties, stable envelopes, andtheir 3d mirror symmetry. <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Mirror symmetry for 3d N=4SUSY QFTs has recently received much attention in geometry and representation theory. Theories within this class give rise to interesting moduli spaces of vacua, whose most relevant components are called the Higgs and Coulomb branches. Nakajima initiated themathematical study of Higgs branches in the 90s; since then, their geometry has been pivotal in diverse areas of enumerative geometry and geometric representation theory. On the other hand, a mathematically precise definition of the Coulomb branch has onlyrecently been proposed, and its study has started. Physically, 3d mirror symmetryis understood as a duality for pairs of theories whose Higgs and Coulomb branches are interchanged. Mathematically, it descends to a number of statements relating invariants attached to the dual sides. One of its key predictions is the identification of dualpairs of elliptic stable envelopes, which are certain topological classes intimately related to elliptic quantum groups. </div><div class="event_time">13:15 &bull; EPF Lausanne, MA A1 12</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"> Xinwei  Shen (ETH Zurich)</div><div class="event_title">Engression: Extrapolation for Nonlinear Regression? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Extrapolation is crucial in many statistical and machine learning applications, as it is common to encounter test data outside the training support. However, extrapolation is a considerable challenge for nonlinear models. Conventional models typically struggle in this regard: while tree ensembles provide a constant prediction beyond the support, neural network predictions tend to become uncontrollable. This work aims at providing a nonlinear regression methodology whose reliability does not break down immediately at the boundary of the training support. Our primary contribution is a new method called ‘engression’ which, at its core, is a distributional regression technique for pre-additive noise models, where the noise is added to the covariates before applying a nonlinear transformation. Our experimental results indicate that this model is typically suitable for many real data sets. We show that engression can successfully perform extrapolation under some assumptions such as a strictly monotone function class, whereas traditional regression approaches such as least-squares regression and quantile regression fall short under the same assumptions. We establish the advantages of engression over existing approaches in terms of extrapolation, showing that engression consistently provides a meaningful improvement. Our empirical results, from both simulated and real data, validate these findings, highlighting the effectiveness of the engression method. The software implementations of engression are available in both R and Python. </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://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">Prof. Dr. Georgios Moschidis (EPFL)</div><div class="event_title">Weak turbulence on Schwarzschild-AdS spacetime <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />\'\'In the presence of confinement, the Einstein field equations are expected to exhibit turbulent dynamics. The simplest example of such behaviour is described by the AdS instability conjecture, put forward by Dafermos and Holzegel in 2006; this conjecture suggests that generic small perturbations of the AdS initial data lead to the formation of trapped surfaces when reflecting boundary conditions are imposed at conformal infinity. However, whether a similar scenario also holds in the more complicated case of the exterior region of an asymptotically AdS black hole spacetime has been the subject of debate. In this talk, we will show that weak turbulence does emerge in the dynamics of a quasilinear toy model for the vacuum Einstein equations on the Schwarzschild-AdS exterior spacetimes for an open and dense set of black hole mass parameters. This is joint work with Christoph Kehle.</div><div class="event_time">16:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.ethz.ch/mathematik-und-ausbildung/weiterbildung/kolloquium.html">Kolloquium über Mathematik, Informatik und Unterricht</a></div><br /><div class="event_speaker"> Dennis Komm (ETH Zürich)</div><div class="event_title"> Informatikunterricht gestern, heute und morgen <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> Im August 2024 wird Informatik zum «Grundlagenfach» an Schweizer Gymnasien.  In diesem Vortrag werde ich die Geschichte des Informatikunterrichts zusammenfassen (die gar nicht so jung ist, wie man meinen könnte) und eine Vision davon skizzieren, welche Rolle die Informatik in den Schulen der Zukunft spielen wird.  Ferner werden einige Fehlvorstellungen diskutiert, die sich beispielsweise ergeben, wenn Begriffe wie «Variable» oder «Gleichung» aus der Mathematik auf den Programmierunterricht treffen.</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.1</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://math.ethz.ch/s/talks-in-financial-and-insurance-mathematics">Talks in Financial and Insurance Mathematics</a></div><br /><div class="event_speaker"><a class="external" href="https://perso.math.univ-toulouse.fr/areveill/">Prof. Dr. Anthony Réveillac (INSA Toulouse)</a></div><div class="event_title">Pseudo-chaotic expansion and explicit correlation formula for the Hawkes processes <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Hawkes processes have proved to be a powerful probabilistic model for various applications in neurosciences or insurance. These counting processes are defined through their intensity which is stochastic and pathwise dependent on the historical values of the process itself. This implicit definition leads to important drawbacks for performing explicit calculations involving simple quantities like for instance the inter-temporal correlation for which nothing is known to our knowledge outside the stationary case and some very particular examples. In this talk based on a joint work with C. Hillairet (ENSAE Paris), we will fill this gap by exploiting a specific decomposition named pseudo-chaotic expansion mixing some pathwise calculus together with some Malliavin calculus obtained in a previous joint work.</div><div class="event_time">17:15 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 43</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Friday, December 1      </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>';