Past colloquia

Colloquium program from August 2016 to January 2017

[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

Other events from August 2016 to January 2017

[workshop] September 5-7 2016 - Pérolles campusmore


[oberseminar] 10:20, Math II (Lonza)more

Zoé Philippe (Nantes): Maximal radius of quaternionic hyperbolic orbifold

[oberseminar] Wed 28.09.2016, Math II (Lonza) at 10:20more

Gaëtan Borot (MPI Bonn): Around a Riemann-Hilbert problem in P1 related to Seifert spaces

Wj(z + i0) + Wj(z - i0) + åk ¹ j Tj,kWk(z) = V(z)     (0)
where Tj,k are real constants and V(z) a given meromorphic 1-form on P1. There are many situations in mathematical physics where we desire to solve such problems, as explicitly as possible, for specific T_j,k and V, and I will first give some motivations from random matrices, random lozenge tilings in 2d, 3-manifold invariants, ... I will explain an elementary approach to *, which in favorable (but not so common) cases lead to a full solution. * is indeed an instance of Riemann-Hilbert problem. It indeed allows us the construction of the monodromy group G of the solution (W_j), and it is then the matter of finding functions with prescribed monodromy and singularities. G here is a pseudo-reflection group defined by n generators, and has a natural action on an n-dimensional vector space. In case the group admits a non-trivial finite orbit (which can happen even if G is infinite), the solutions can be described by algebro-geometric methods. Given T_j,k, we are therefore interested in identifying the group G, as well as its set of (finite or maybe not) orbits. The third part of the talk will focus on a class of examples of T_j,k, attached to Seifert spaces. These are S1-bundles over an orbifold S2. Important geometric invariants of those spaces are the order of orbifold points on the base surface (a_1,...,a_r), and the orbifold Euler characteristic c = 2 - r + å_i 1/a_i. The geometrical type (spherical, euclidean, hyperbolic) of the 3-manifold is determined with a few exceptions by the sign of c. It turns out that the large N limit (and actually the full large N expansion) of the SU(N) evaluation of LMO invariants of these Seifert spaces is determined by a solution to * for T_j,k determined by a_1,...,a_r. We find that the corresponding G, although not finite, admits finite orbits if and only if c is nonnegative, and in these case solutions can (almost) effectively be computed, implying some algebraicity for LMO invariants. Many questions yet remain open about identification of G, both for c > 0 and c < 0, its relation to the geometry of the underlying Seifert space, and how to solve * in the cases for c < 0. This is based on a joint work with Bertrand Eynard.

[oberseminar] Wed 19.10.2016 ,Math II (Lonza) at 10h20more

Masato Mimura (EPFL): Superintrinsic synthesis in fixed point properties

[oberseminar] Wed 26.10.2016, Math II (Lonza) at 10:20more

Felix Schlenk (Neuchatel): Growth of the number of geodesics between two points in manifolds of non-finite type

[mathematikon] Tue 8.11.2016, Phys 2.73 at 12h15more

Joé Brendel: The Geometry of Complex Numbers

[oberseminar] Wed 09.11.2016, Math II (Lonza) at 10h20more

Manfred Lehn (Universität Mainz): Irreducible holomorphic symplectic manifolds from cubic fourfolds

[oberseminar] Wed 23.11.2016, Math II (Lonza) at 10h20more

Stefano Riolo (University of Pisa)

[oberseminar] Wed 30.11.2016, Math II (Lonza) at 10h20more

Edoardo Dotti and Simon Drewitz: Right-Angled Polygons in Hyperbolic Space

[oberseminar] Wed 7.12.2016, Math II (Lonza) at 10h20more

Andrew Yarmola (University of Luxembourg): Hyperbolic 3-manifolds with low cusp volume

[oberseminar] Wed 14.12.2016, Math II (Lonza) at 10h20more

Rafael Guglielmetti (Fribourg): Clifford algebras and isometries of (infinite dimensional) hyperbolic spaces

[oberseminar] Thur, 15.12.2016, Earth Sciences 1.309 at 11h00more

Jamal Najim (LIGM - Université de Marne La Vallée): Non-hermitian random matrices with a variance profile

[oberseminar] Wed 21.12.2016, Math II (Lonza) at 10h20more

Marton Naszodi (EPFL, Lausanne & ELTE, Budapest)

Université de Fribourg - Mathématiques - Ch. du Musée 23, 1700 Fribourg - tél +41 26 / 300 9180
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