Talks and events

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Upcoming talks

[oberseminar] Wed 27.09.2017, Math II (Lonza) at 10h20

Grigory Ivanov (EPFL): The cross-polytope and the cube, their sections and projections

We will speak about different bounds on the volume of a projection of the n-dimensional cross-polytope and a central section of the n-dimensional cube. There are several results about central sections of the cube. However, the dual problems are still open.
For instance, the celebrated Vaaler theorem asserts that the volume of a k-dimensional central section of the n-cube is greater or equal to the volume of the k-cube. But it is not known whether the volume of a k-dimensional projection of the n-dimensional cross-polytope is less or equal to the volume of the k-dimensional cross-polytope.
We will introduce a linear algebra approach to these problems which allows us to find some optimal bounds for the cross-polytope and the cube at the same time. Also we will discuss current view on the problems and formulate some open questions.

[colloque] Tue 3.10.2017, Phys 2.52 at 17h15

Prof. Manfred Trummer (Simon Fraser University Vancouver): tba

[colloque] Mon 9.10.2017

PLANCHEREL LECTURE

[colloque] Tue 17.10.2017, Phys 2.52 at 17h15

Prof. Jamal Najim (Université de Marne La Vallée): Large Random Matrices of Long Memory Stationary Processes: Asymptotics and fluctuations of the largest eigenvalue

Given $n$ i.i.d. samples $(\boldsymbol{\vec x}_1, \cdots, \boldsymbol{\vec x}_n)$ of a $N$-dimensional long memory stationary process, it has recently been proved that the limiting spectral distribution of the sample covariance matrix, $$ \frac 1n \sum_{i=1}^n \boldsymbol{\vec x}_i \boldsymbol{\vec x}^*_i $$ has an unbounded support as $N,n\to \infty$ and $\frac Nn\to c\in (0,\infty)$. As a consequence, its largest eigenvalue $$ \lambda_{\max} \left( \frac 1n \sum_{i=1}^n \boldsymbol{\vec x}_i \boldsymbol{\vec x}^*_i \right) $$ goes to infinity. In this talk, we will describe its asymptotics and fluctuations, tightly related to the features of the underlying population covariance matrix, which is of a Toeplitz nature..

This is a joint work with Peng Tian and Florence Merlevède.

[colloque] Tue 24.10.2017, Phys 2.52 at 17h15

Prof. Omid Amini (ENS Paris): tba

[colloque] Tue 31.10.2017, Phys 2.52 at 17h15

Prof. Jean-Marc Schlenker (Uni Luxembourg): tba

[colloque] Tue 7.11.2017, Phys 2.52 at 17h15

Prof. Christine Bachoc (Bordeaux): Sets avoiding the distance 1 in $\mathbb R^n$

[colloque] Tue 14.11.2017, Phys 2.52 at 17h15

Prof. Yohei Komori (Waseda Univ, Tokyo): Growth functions of hyperbolic groups

[colloque] Tue 21.11.2017, Phys 2.52 at 17h15

Prof. Valentin Féray (Uni Zürich): tba

[colloque] Tue 28.11.2017, Phys 2.52 at 17h15

Prof. Urs Lang (ETHZ): tba

[colloque] Tue 12.12.2017, Phys 2.52 at 17h15

Prof. Maryna Viazovska (EPFL): tba

[colloque] Tue 19.12.2017, Phys 2.52 at 17h15

Sophie Hautphenne (Melbourne / EPFL): tba

Archive:

Colloquia in the current semester

[colloque] Tue 1.3.2016, Phys 2.52 at 17h15 - Festvortrag zum 80. Geburtstag von Ernst Ruhmore

Prof. Dr. Ernst Heintze (Uni Augsburg): Affine root systems and submanifolds of Hilbert spaces

[colloque] Tue 8.3.2016, Phys 2.52 at 17h15more

Prof. Joan Porti (Barcelona): Reidemeister torsion and hyperbolic 3-manifolds

[colloque] Tue 22.3.2016, Phys 2.52 at 17h15more

Prof. Uwe Semmelmann (Uni. Stuttgart): Invariant 4-forms and exceptional Lie algebras

[colloque] Tue 12.4.2016, Phys 2.52 at 17h15more

Prof. Dr. Benjamin Sudakov (ETH Zürich): Induced matchings, arithmetic progressions and communication

[colloque] Tue 19.4.2016, Phys 2.52 at 17h15more

Prof. Christophe Bavard (Bordeaux): Points conjugués en géométrie riemannienne et lorentzienne

[colloque] Tue 26.4.2016, Phys 2.52 at 17h15more

Prof. Roman Sauer (KIT): Invariant random subgroups

[colloque] Tue 3.5.2016, Phys 2.52 at 17h15more

Prof. Hans Josef Pesch (Uni Bayreuth): Optimal Control of Dynamical Systems Governed by Partial Differential Equations

[colloque] Tue 10.5.2016, Phys 2.52 at 17h15more

Prof. Sergiu Moroianu (Bucharest): Renormalized volume in hyperbolic geometry

[colloque] Tue 17.5.2016, Phys 2.52 at 17h15more

Prof. Vincent Beffara (CNRS Grenoble): Introduction to the Schramm-Loewner Evolution

[colloque] Tue 24.5.2016, Phys 2.52 at 17h15more

Dr. Roger Zuest (Fribourg): Regularity theory for almost minimal surfaces

[colloque] Tue 31.5.2016, Phys 2.52 at 17h15more

Prof. Wolfgang Lück (Universität Bonn / HIM Bonn): Introduction to $L^2$-Betti numbers

[colloque] Tue 7.6.2016, Phys 2.52 at 15h30more

Prof. Alexandru Suciu (Northeastern University, Boston): Fundamental groups in algebraic geometry and three-dimensional topology

[colloque] Tue 20.9.2016, Phys 2.52 at 17h15more

Prof. Daniel Grieser (Universität Oldenburg): A look at triangles from elementary geometry, spectral theory and singular analysis

[colloque] Tue 27.9.2016, Phys 2.52 at 17h15more

Prof. Christoph Böhm (Universität Münster): Immortal homogeneous Ricci flows

[colloque] Tue 11.10.2016, Phys 2.52 at 17h15more

Prof. Gerhard Opfer (Universität Hamburg): Zeros of unilateral quaternionic and coquaternionic polynomials

[colloque] Tue, 25.10.2016, Phys 2.52 at 17h15more

Dr. Wim Hordijk (Konrad Lorenz Institut, Klosterneuburg): Autocatalytic Sets: The Origin and Organization of Life

[colloque] Tue 8.11.2016, Phys 2.52 at 17h15more

Prof. Manfred Lehn (JG Universität Mainz): The theorem of Grothendieck-Brieskorn-Slodowy and symplectic singularities

[colloque] Tue 15.11.2016, Phys 2.52 at 17h15more

Prof. Nicolas Curien (Université Paris-Sud Orsay): A panoramic introduction to random planar maps

[colloque] Tue 22.11.2016, Phys 2.52 at 17h15more

Prof. Masahiko Yoshinaga (Hokkaido University): Characteristic polynomials of hyperplane arrangements

[colloque] Tue 6.12.2016, Phys 2.52 at 17h15more

Prof. Priyam Patel (UCSB): Quantitative methods in hyperbolic geometry

[colloque] Tue 13.12.2016, Phys 2.52 at 17h15more

Prof. Christophe Soulé (IHES): La théorie d'Arakelov

[colloque] Tue 7.3.2017, Phys 2.52 at 17h15more

Prof. Sergei Tabachnikov (Pennsylvania State University): Skewers

[colloque] Tue 14.3.2017, Phys 2.52 at 17h15more

Prof. Philipp Habegger (Uni Basel): Complex Multiplication or is $e^{\pi \sqrt{163}}$ an Integer?

[colloque] Tue 21.3.2017, Phys 2.52 at 17h15more

Prof. Jan Draisma (Uni Bern): Stabilisation in algebra and geometry

[colloque] Tue 28.03.2017, Phys 2.52 at 17h15more

Martin Kerin (Univ. of Münster): Curvature and exotic spheres

[colloque] Tue 4.4.2017, Phys 2.52 at 17h15more

Prof. Armin Iske (Uni Hamburg): Kernel-based Scattered Data Approximation

[colloque] Tue 25.4.2017, Phys 2.52 at 17h15more

Prof. Antti Knowles (Uni Genève): Extreme eigenvalues of sparse random graphs

[colloque] Tue 16.5.2017, Phys 2.52 at 17h15more

Prof. Pierre Nolin (ETHZ): Near-critical percolation and self-organized criticality in two dimensions

[colloque] Tue 30.5.2017, Phys 2.52 at 17h15more

Prof. Gerhard Wanner (Uni Genève): Porous media modelling with a 250 years old method

Other talks and events in the current semester

[oberseminar] Oberseminar Geometrie, Wed 4.3.2015, Math II (Lonza) at 10:20more

Martin Herrmann (Fribourg): Almost nonnegative curvature operator, homogeneous spaces and a question of Karsten Grove

[oberseminar] Oberseminar Geometrie, Wed 11.3.2015, Math II (Lonza) at 10:20more

Mike Roberts (Durham): A methodical approach to the construction of Coxeter polytopes in hyperbolic n-space with n+3 facets

[oberseminar] Combinatorics seminar, Fri 13.3.2015, Math II (Lonza) at 13:15more

Ornella greco (KTH Stockholm): The Betti table of Veronese Modules

[oberseminar] Oberseminar Geometrie, Wed 18.3.2015, Math II (Lonza) at 10:20more

Kate Juschenko (Northwestern): Techniques and concepts of amenability of discrete groups

[oberseminar] Oberseminar Geometrie, Wed 26.3.2015, Math II (Lonza) at 10:20more

Stefan Rosemann (Jena): Kähler metrics with Hamiltonian 2-forms, their classification via projectively equivalent metrics and applications

[oberseminar] Oberseminar Geometrie, Wed 15.4.2015, Math II (Lonza) at 10:20more

Bernhard Mühlherr (Giessen): Tits-indices, affine Coxeter groups and buildings

[oberseminar] Oberseminar Geometrie, Wed 22.4.2015, Math II (Lonza) at 10:20more

Viktoriya Ozornova (Bremen / MPIM Bonn): Factorability structures

[oberseminar] Combinatorics seminar, Fri 24.04.2015, Time and place TBAmore

Matteo Varbaro (Genova): On dual graphs of complete intersections

[oberseminar] Oberseminar Geometrie, Wed 29.4.2015, Math II (Lonza) at 10:20more

Jordane Granier (Fribourg): Sous-groupe discret de PU(2,1) avec l'éponge de Menger pour ensemble limite

[oberseminar] Oberseminar Geometrie, Wed 6.5.2015, Math II (Lonza) at 10:20more

Vincent Emery (EPF Lausanne): Volumes des variétés hyperboliques et actions de Galois

[oberseminar] Oberseminar Geometrie, Wed 20.5.2015, Math II (Lonza) at 10:20more

Misha Wasem (ETHZ): Isometric extensions at low regularity and codimension

[oberseminar] Oberseminar Geometrie, Wed 27.5.2015, Math II (Lonza) at 10:20more

Martin Deraux (Grenoble): Groupes de triangles en géométrie hyperbolique complexe

Université de Fribourg - Mathématiques - Ch. du Musée 23, 1700 Fribourg - tél +41 26 / 300 9180      isabella.schmutz@unifr.ch
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