var sms = '<div id="sms_bulletin">  <div id="sms_header">  <div class="do_not_print" id="arrow_left"><a href="?next=-15"><img src="//www2.math.ethz.ch/smsjs/images/arrow_left.png"/></a></div><div class="do_not_print" id="arrow_right"><a href="?next=-13"><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. 1</span>      <span style="float: right; text-align:right; width: 250px;">15.9 - 19.9.2025</span>      <span style="text-align: center; display: block; width: 250px; margin: auto; position: relative;">Autumn Semester 2025</span>    </div>  </div>  <div></div>  <div id="sms_content">    <div class="day">      <div class="day_title">        Monday, September 15      </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://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Artur Riazanov</div><div class="event_title">Sampling Permutations with Cell-Probes is Hardas for communication complexity <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Generating uniformly random permutations is a very basic task that is routinely done in randomized algorithms, there is a very simple algorithm that does it in linear time. Doing this in parallel is more challenging with a vast literature including non-trivial upper bounds in switching networks (Czumaj, STOC 2015), low-depth circuits (Hagerup, ALP 1991), EREW PRAM (Czumaj, Kanarek, Kuty&#322;owski, Lory&#347;, SODA 1999). We study this question in the cell-probe model: given an unlimited supply of uniform symbols in [n], generate the elements of a permutation S_n by making several probes (queries) to the uniform string for each output symbol. Before our work it was not known if sampling is possible with two probes. The challenge to show this impossibility was posed by Viola (SICOMP 2020), who gave a log log n lower bound for the case of non-adaptive probes. The non-adaptive bound was later improved by Yu and Zhan (ITCS 2024) to almost log n. We show two lower bounds (1) superconstant for the adaptive case (2) polynomial for the non-adaptive case.  Both of our results yield new lower bounds for succinct data structures.   This is joint work with Yaroslav Alekseev, Mika Göös, Konstantin Myasnikov, and Dmitry Sokolov.</div><div class="event_time">11:00 &bull; EPF Lausanne, INJ114</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_la"><a class="external" href="https://www.epfl.ch">EPF Lausanne</a></div><div class="event_type"><a class="external" href="https://www.epfl.ch/schools/sb/research/math/events/">Seminar in Mathematics </a></div><br /><div class="event_speaker"> Dimitry  Wyss</div><div class="event_title">On some geometric applications of non-archimedean integrals <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />There are many instances where the topology of algebraic varieties encodes structures relevant for other areas of mathematics. For example, the (intersection) cohomology of toric varieties is closely related to the combinatorics of convex polytopes and the representation theory of finite groups of Lie types can be understood through the étale cohomology of Deligne-Lusztig varieties.Non-archimedean integration, as pioneered by Denef-Loeser, Batyrev and Kontsevich, provides a fascinating tool to study such cohomological invariants. In my talk I will explain the basic principles, advantages and limitations of the theory before mentioning some of our own contributions. In particular I will discuss work with Francesca Carocci, Michael Groechenig, Paul Ziegler which leads to a non-archimedean reinterpretation of the so-called BPS-numbers in the enumerative geometry of Calabi-Yau 3 folds.</div><div class="event_time">14:30 &bull; EPF Lausanne, CM 1 517</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Tuesday, September 16      </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"> Tullio  Ceccherini-Silberstein  (Università di Beneveto)</div><div class="event_title">A Garden of Eden Theorem for Smale Spaces <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Smale spaces were introduced in the late 1970s by David Ruelle in his influential monograph on thermodynamic formalism.These dynamical systems include: Anosov diffeomorphisms, non-wandering sets of Smale\'s Axiom A diffeomorphisms, various types of solenoids and  attractors, as well as (in a symbolic dynamical setting) subshifts of finite type.In a recent joint work with Michel Coornaert, we proved, among other things, a Garden of Eden type theorem (GOET) for irreducible Smale spaces. This generalizes previous results by Fiorenzi (GOET for irreducible subshisfts of finite type) and ours (GOET for Anosov diffeomorphisms on tori).</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_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"> Luan  Jahija (Université de Genève)</div><div class="event_title">Impacts of thermal pressurization during earthquakes based on a numerical analysis <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Earthquakes are among the most powerful and destructive natural phenomena, driven by complex interactions along Earth’s tectonic faults.We investigate the physical mechanisms that govern earthquake dynamics, with a particular focus on the role of thermal pressurization in fault zones. When two tectonic plates slide against each other, the extreme conditions of friction and temperature alter the pressure of fluids trapped within the rock, directly influencing fault stability and rupture propagation.Using numerical modelling, we developed and analysed equations describing these complex processes. We began with simplified friction models based on Amonton–Coulomb’s law and then introduced more realistic rate-and-state friction laws. The models were progressively extended to incorporate the effects of thermal diffusion, pore fluid pressure, and chemical reactions within rocks.The simulations highlight how different physical parameters such as thermal diffusivity or fluid generation affect the transition between stable (creeping) and unstable (seismic rupture) behaviour. This work contributes to a better understanding of the conditions that favour earthquake initiation and amplification, bridging the gap between simple theoretical models and observed geophysical processes.</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/analysis-seminar">Analysis Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Yannick Sire (Johns Hopkins University)</div><div class="event_title">Regularity vs singularity formation for harmonic map heat flows with free boundaries <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 results on geometric flows associated to harmonic mappings with free boundary.Those maps are instrumental in several geometric problems, such as extremal metrics for the Steklov spectrum for instance and one can formulate several possible parabolic equations whose stationnary solutions are such maps.I will describe these formulations, each of which offering interesting applications and analytic problems. In various cases, one can derive partial regularity results for weak solutions and describe the structure of the singular set. I will try to give an overview of such results. However, a formulation, related to the Plateau flow, poses more challenging issues and I will formulate some conjectures about its singularity formation. The construction of solutions blowing up in finite or infinite time uses a new gluing technique, which has been successfully used recently to investigate singularity formations in other flows, such as Fast Diffusion equations or Yang-Mills heat flow.</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_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"> Andre Laestadius</div><div class="event_title">Smoothing the Landscape: Moreau-Yosida Regularization in Modern Density-Functional Theory <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />In the standard convex&#8209;analytic formulation of density&#8209;functional theory the universal functional is non&#8209;smooth, complicating the connection to a practical scheme. We apply Moreau–Yosida regularisation that adds a quadratic penalty term to obtain smooth approximants of the functional whose derivatives are Lipschitz&#8209;continuous and converge to the exact functional as the regularisation parameter goes to zero. This regularity enables a framework for inversion to obtain the Kohn&#8209;Sham "effective" potential utilizing the proximal map that is a crucial ingredient of Moreau–Yosida regularisation. This can also be done in practice using a plane&#8209;wave basis.References:Herbst, M.F., Bakkestuen, V.H. and Laestadius, A., 2025. Kohn-Sham inversion with mathematical guarantees. Physical Review B, 111(20), p.205143.   Penz, M. and Laestadius, A., 2026. Adaptation of Moreau–Yosida regularization to the modulus of convexity. Journal of Mathematical Analysis and Applications, 554(2), p.129956</div><div class="event_time">16:15 &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://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">Ibrahim Trifa (ETH)</div><div class="event_title">What is... the Lagrangian Hofer norm? <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>&lt;span style="color: black; font-size: 12pt; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif;" data-olk-copy-source="MessageBody">Given a Lagrangian inside a symplectic manifold, one can define a metric, called the Hofer distance, on the space of Hamiltonian isotopies of this Lagrangian. It is known to be bounded in the case of a circle inside the plane, while it is unbounded for a diameter inside the disc (Khanevsky, 2009), or the standard Lagrangian inside the Euclidean ball of even dimension (Seyfaddini, 2013). The question remains open in most cases, such as the equator inside the sphere or a circle inside the disc. In this talk, I will show the unboundedness of this distance for a disjoint union of circles inside the disc. This result relies on a theorem of Morabito, together with a standard argument of Khanevsky.&lt;/span>&lt;/p></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, September 17      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://uzh.ch">Universit&auml;t Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat760">Ergodic theory and dynamical systems seminar</a></div><br /><div class="event_speaker">Prof. Dr. Ilya Gekhtman (Technion - Israel Institute of Technology)</div><div class="event_title">Linearly growing injectivity radius in negatively curved manifolds with small critical exponent. <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;div dir="ltr">Let X be a proper geodesic Gromov hyperbolic space whose isometry group contains a uniform lattice \\Gamma.&nbsp;&lt;/div> &lt;div dir="auto">For instance, X could be a negatively curved contractible manifold or a Cayley graph of a hyperbolic group.&lt;/div> &lt;div dir="ltr">Let H be a discrete subgroup of isometries of X with critical exponent (exponential growth rate) strictly less than half of the growth rate of \\Gamma.&nbsp;&lt;/div> &lt;div dir="ltr">&nbsp;We show that the injectivity radius of X/H grows linearly along almost every geodesic in X (with respect to the Patterson-Sullivan measure on the Gromov boundary of X).&lt;/div> &lt;div dir="ltr"> &lt;div>The proof will involve an elementary analysis of a novel concept called the "sublinearly horosherical limit set" of H which is a generalization of the classical concept of "horospherical limit set" for Kleinian groups.&lt;/div> &lt;div>&nbsp;&lt;/div> &lt;div>&nbsp;&lt;/div> &lt;div>This talk is based on joint work with Inhyeok Choi and Keivan Mallahi-Kerai.&lt;/div> &lt;/div></div><div class="event_time">13:30 &bull; UZH Irchel, Winterthurerstrasse 190, Z&uuml;rich, Building Y27, Room H 28</div>        </div>        <div class="day_content_item normal"><div class="event_location uni_ne"><a class="external" href="https://unine.ch">Université de Neuchâtel</a></div><div class="event_type"><a class="external" href="https://www.unine.ch/math/home/colloques_et_seminaires/seminaires-de-linstitut.html">Séminaire de Géométrie et Systèmes dynamiques </a></div><br /><div class="event_speaker">Dr. Jean-Philippe  Chassé (ETH Zürich)</div><div class="event_title">Quelques propriétés du flux lagrangien <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Associé à une isotopie lagrangienne, c.-à-d. un chemin de plongements lagrangiens, est le flux lagrangien. Cependant, contrairement au cas des isotopies symplectiques, ce flux ne définit pas en général un homomorphisme sur le groupe fondamental de l\'espace des lagrangiennes dans une variété symplectique. Nous explorerons la raison pour laquelle cela est le cas — la monodromie — et comment cela est lié aux propriétés topologiques de l\'orbite hamiltonienne de la lagrangienne. Nous conclurons avec certains calculs en dimension 4. Ce projet est en commun avec Joé Brendel et Rémi Leclercq.</div><div class="event_time">14:00 &bull; Université de Neuchâtel, Rue Emile-Argand 11, Room B217</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"> Rajen Shah (University of Cambridge, UK)</div><div class="event_title">Hunt and test for assessing the fit of semiparametric regression models <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />We consider testing the goodness of fit of semiparametric regression models, such as generalised additive models, partially linear models, or quantile additive regression models. We propose an approach that involves first splitting the data in two parts. On one part, we "hunt" for any signal that may be present in the score-type residuals following a fit of the model. On the remaining data, we test for the presence of the potential signal thus found. For the first hunting stage of the procedure, our framework allows for carrying this out based on a user-chosen flexible regression method, such as a random forest. The method is thus able to leverage the power of modern machine learning methods to detect complex alternatives. A challenge with the testing step is that any first-order bias in the residuals may lead to rejection under the null. We therefore employ a debiasing step which we show amounts to performing a particular weighted least squares regression. We show that the type I error may be controlled under relatively mild conditions, and that we have power under alternatives where with high probability the hunted signal is correlated with the true signal present in the score residuals.</div><div class="event_time">15:15 &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/sam/news-and-events/zhacm-colloquia">Zurich Colloquium in Applied and Computational Mathematics</a></div><br /><div class="event_speaker"> Gil Goldshlager (U.C. Berkeley, USA)</div><div class="event_title">Understanding and Accelerating Subsampled Natural Gradient Algorithms for Scientific Machine Learning <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Over the last two years, subsampled natural gradient descent (SNGD) has demonstrated breakthrough performance for parametric optimization tasks in scientific machine learning, including neural network wavefunctions and physics-informed neural networks. In this talk, I will first present an accelerated algorithm called SPRING which improves the convergence of SNGD at no extra cost. I will then consider the theoretical aspects of these algorithms and explain why previous analytical approaches based on stochastic optimization theory fail to explain the empirical observations. Finally, I will show how a different perspective rooted in randomized linear algebra overcomes these limitations and provides an accurate and detailed understanding of the convergence properties of both SNGD and SPRING. Beyond explaining existing algorithms, the new analytical framework also suggests new pathways towards faster and more robust training algorithms for scientific machine learning</div><div class="event_time">16:30 &bull; ETH Zentrum, R&auml;mistrasse 101, Z&uuml;rich, Building HG, Room G 19.2</div>        </div>      </div>    </div>    <div class="day">      <div class="day_title">        Thursday, September 18      </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://theory.epfl.ch/seminar/">Theory and Combinatorics Seminar</a></div><br /><div class="event_speaker"> Kaave Hosseini (Rochester)</div><div class="event_title">Algebraic, Analytic, and Combinatorial Complexity of Boolean Matrices <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br /> Boolean matrices are fundamental objects in computer science and discrete mathematics.  Numerous measures have been developed to capture the complexity of a Boolean matrix, each tailored to specific applications. These measures can be broadly categorized as algebraic (e.g., notions of rank), analytic (e.g., norms), and combinatorial (e.g., communication complexity). Many important open problems in theoretical computer science are, at their core, about understanding the relationships between these categories. Here I discuss a number of such results and open problems related to communication complexity, learning theory, dimensionality reduction, and algorithms.</div><div class="event_time">11:00 &bull; EPF Lausanne, BC 229</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"> Pierre Descombes</div><div class="event_title">Thom-Sebastiani theorem in the motivic world <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />Sebastiani and Thom proved, in the complex analytic setting, thatthe vanishing cycle of f+g is the product of the vanishing cycles of f and g.In the motivic world, Deligne has observed that such a formula cannot hold,unless one considers instead the convolution product with respect to themonodromy. This formula was then obtained for étale sheaves by Illusie, and formixed Hodge modules by Saito. We will present here a proof working forMorel-Voevodsky motivic stable homotopy theory (SH), using deep results ofAyoub. Passing to the Grothendieck group, one obtains the Thom-Sebastianitheorem of Denef-Loeser-Looijenga.We will then explain how, using this result, vanishing cycles ofquadratic forms give square roots of Thom twists, generalizing the results ofDeligne for étale sheaves. We will then sketch how these results could be usedto upgrade cohomological DT theory at the level of SH, up to some importantorientation issues.</div><div class="event_time">13:15 &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://k-os.math.ethz.ch">[K-OS] Knot Online Seminar</a></div><br /><div class="event_speaker"> Ciprian Manolescu (Stanford University)</div><div class="event_title">Real Heegaard Floer Homology</div><div class="event_time">16:15 &bull; <a class="external" href="https://u-paris.zoom.us/j/87853056962">online</a></div>        </div>        <div class="day_content_item normal"><div class="event_location uni_zh"><a class="external" href="https://ethz.ch">ETH Z&uuml;rich</a></div><div class="event_type"><a class="external" href="https://www.math.uzh.ch/mat675.1">PDE and Mathematical Physics</a></div><br /><div class="event_speaker">Raphael Winter (Cardiff University)</div><div class="event_title">Between Landau damping and parabolic regularity: kinetic equations for plasma <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />&lt;p>We will discuss recent advances on the mathematical kinetic theory of plasma. First, we will present a new Landau damping result for the (screened) Vlasov-Poisson equation in the presence of an ion, justifying the stopping power law in plasma physics. Since the equation is non-dissipative and time-reversible, the key challenge lies in a detailed study of dispersion/phase-mixing.<br />This is in contrast to the collisional kinetic equations for plasma, which are parabolic PDEs formally satisfying an entropy dissipation theorem. We present new results on the regularity and well-posedness of the Landau- and Balescu-Lenard equations, featuring a new blow-down mechanism for singular data. Based on joint works with M. Duerinckx, M.P. Gualdani and R. H&ouml;fer.&lt;/p></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>    </div>    <div class="day">      <div class="day_title">        Friday, September 19      </div>      <div class="day_content">        <div class="day_content_item normal"><div class="event_location uni_ba"><a class="external" href="https://unibas.ch">Universität Basel</a></div><div class="event_type"><a class="external" href="https://dmi.unibas.ch/de/forschung/mathematik/seminar-in-numerical-analysis">Seminar in Numerical Analysis</a></div><br /><div class="event_speaker"> Niraj Kumar Shukla (Indian Institute of Technology Indore)</div><div class="event_title"><a class="external" href="https://dmi.unibas.ch/de/news-events/detail/seminar-in-numerical-analysis-niraj-kumar-shukla-indian-institute-of-technology-indore/">Construction of pairwise orthogonal Parseval frames generated by filters on LCA groups</a> <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />The generalized translation invariant (GTI) systems unify the discrete frame theory of generalized shift-invariant systems with its continuous version, such as wavelets, shearlets, Gabor transforms, and others. This article provides sufficient conditions to construct pairwise orthogonal Parseval GTI frames in satisfying the local integrability condition (LIC) and having the Calderón sum one, where G is a second countable locally compact abelian group. The pairwise orthogonality plays a crucial role in multiple access communications, hiding data, synthesizing superframes and frames, etc. Further, we provide a result for constructing N numbers of GTI Parseval frames, which are pairwise orthogonal. Consequently, we obtain an explicit construction of pairwise orthogonal Parseval frames in and , using B-splines as a generating function. In the end, the results are particularly discussed for wavelet systems. This is a joint work with Navneet Redhu and Anupam Gumber. For further information about the seminar, please visit this webpage .</div><div class="event_time">11:00 &bull; Universität Basel, Room 05.001, Spiegelgasse 5, 4051 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/number-theory-seminar">Number Theory Seminar</a></div><br /><div class="event_speaker">Prof. Dr. Adam Morgan (Cambridge)</div><div class="event_title">On the Hasse principle for degree 4 del Pezzo surfaces  <span class="abstract-button do_not_print">abstract</span></div><div class="abstract-text" style="display: none"><strong>Abstract:</strong><br />I will discuss recent work with Skorobogatov, and work in progress with Lyczak, establishing the Hasse principle for classes of degree 4 del Pezzo surfaces, conditional on finiteness of certain Tate--Shafarevich groups. Key to the method is the study of an auxiliary family of Kummer surfaces. </div><div class="event_time">14:15 &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>';