Math Calendar

Thursday, November 15, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Alden Waters (RUG) - Inverse Problems for Coupled Systems of Wave Equations, HFG 409
Title: Inverse problems for coupled systems of wave equations

Abstract: We consider coupled systems of semi linear wave equations and discuss the notion of short time well posed ness for the system. Under the assumption of small Cauchy data we show the source to solution map for the nonlinear problem determines the source to solution map for the linear problem. We discuss why the assumption of small data and short times allows us to recover multiple sound speeds uniquely for the nonlinear problem in some natural settings.
Tuesday, November 20, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Georg Oberdieck (MIT/Bonn) - CHL Calabi-Yau threefolds
A CHL Calabi-Yau threefold is the quotient of the product K3xE by an order N automorphism
which acts symplectically on the K3 surface and by shifting by an N-torsion point on the
elliptic curve E. In this talk I will present a conjectural relation between the Donaldson-Thomas theory of CHL models with the twined elliptic genera which appear in Mathieu moonshine.
Part of the conjecture exactly matches predictions by string theory, but not all geometric
cases are covered by the physics formula and new Siegel modular forms appear.
Joint work with Jim Bryan.
Thursday, November 22, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Matthias Schlottbom (U Twente) - A perfectly matched layer approach for radiative transfer in highly scattering regimes, HFG 409
Title: A perfectly matched layer approach for radiative transfer in highly scattering regimes

Abstract: We consider the numerical approximation of boundary conditions in radiative transfer problems by a perfectly matched layer approach. The main idea is to extend the computational domain by an absorbing layer and to use an appropriate reflection boundary condition at the boundary of the extended domain. A careful analysis shows that the consistency error introduced by this approach can be made arbitrarily small by increasing the size of the extension domain or the magnitude of the artificial absorption in the surrounding layer. A particular choice of the reflection boundary condition allows us to circumvent the half-space integrals that arise in the variational treatment of the original vacuum boundary conditions and which destroy the sparse coupling observed in numerical approximation schemes based on truncated spherical harmonics expansions. A combination of the perfectly matched layer approach with a mixed variational formulation and a PN-finite element approximation leads to discretization schemes with optimal sparsity pattern and provable quasi-optimal convergence properties. As demonstrated in numerical tests these methods are accurate and very efficient for radiative transfer in the scattering regime.
(this is joint work with Herbert Egger, TU Darmstadt)
Friday, November 23, 2018
13:00-18:00
MIN 201
55th Seminar on Automorphic Forms and Intercity Number Theory Seminar (a-d)
13:15-14:15
(a) Peter Bruin (Leiden) - On explicit computations with modular Galois representations
14:15-15:15
(b) Alexandru Ciolan (Koln) - Asymptotics and inequalities for partitions into squares
15:45-16:45
(c) Jan-Willem van Ittersum (Utrecht) - A symmetric Bloch-Okounkov theorem
16:45-17:45
(d) Annalena Wernz (Aachen) - On Hermitian modular forms; theta series and Maass spaces
Saturday, November 24, 2018
10:00-16:00
Symposium Ars et Mathesis
Tuesday, November 27, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Shabnam Akhtari (University of Oregon/MPIM Bonn) - Representation of integers by binary forms, HFG 611
Abstract:
Let F(x, y) be an irreducible binary form with integer coefficients and of degree at least 3. By a well known result of Thue, the equation F(x, y) = m has only finitely many solutions in integers x and y. I will discuss some old and new quantitative results on the number of solutions of such equations. I will also talk about my joint work with Manjul Bhargava, where we use these bounds to show that many equations of the shape F(x, y) = m have no solutions.
Thursday, November 29, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Chris Stolk (UvA) - TBA, HFG 409
Tuesday, December 4, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Katrin Wendland (Albert-Ludwigs-Universität Freiburg) - t.b.a., HFG 611
Thursday, December 6, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Maria Predari (Universität zu Köln) - TBA, HFG 409
Tuesday, December 11, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Giovanni Bazzoni (Universidad Complutense de Madrid)- Geometry and Rational Homotopy Theory
This talk would like to be a celebration of the fruitful interplay between Geometry and Rational Homotopy Theory. In order to show how these two areas can work together, I will consider two concrete situations :
(a) the existence of a geometric structure on a compact manifold can be helpful in addressing problems coming from rational homotopy theory, such as the toral rank conjecture ;
(b) rational homotopy theory helps to identify compact manifolds which admit a specific geometric structure, for instance Kähler, Sasakian or Vaisman. This is particularly transparent in the case of nilmanifolds.
Thursday, December 13, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Bob Rink (UvA) - TBA, HFG 409
Tuesday, December 18, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Franziska Jahnke (Universität Münster) - t.b.a., HFG 611
Tuesday, January 8, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Thursday, January 10, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Oliver Tse (TU/e) - TBA, HFG 409
Tuesday, January 15, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Adrien Sauvaget (Universiteit Utrecht) - t.b.a., HFG 611
Tuesday, January 22, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Erik van den Ban (Universiteit Utrecht) - t.b.a., HFG 611
Tuesday, January 29, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Steffen Müller (Universiteit Groningen) - t.b.a., HFG 611
Thursday, January 31, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Svetlana Dubinkina (CWI) - TBA, HFG 409
Tuesday, February 5, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Magdalena Kedziorek - t.b.a., HFG 611
Thursday, February 7, 2019
12:00-13:00
Utrecht
Complex Systems Seminar
Arjan van der Schaft (RUG) - TBA, Min 4.16
15:30-16:30
Staff colloquium
Hector Pasten (PUC, Chile) - t.b.a., MIN 2.01
Tuesday, February 12, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Natalia García-Fritz (PUC, Chile) - t.b.a., HFG 611
Thursday, February 14, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Felix Beckebanze (UU) - TBA, HFG 611
Tuesday, February 19, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Emily Norton (Universität Bonn) - t.b.a., HFG 611
Tuesday, February 26, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Elba García Failde (CEA Saclay) - t.b.a., HFG 611
Tuesday, March 5, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Rahul Pandharipande (ETH Zuerich) - t.b.a., HFG 611
Thursday, March 7, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Caterina Zeppieri (Universität Münster) - TBA, HFG 611
Tuesday, March 12, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Thursday, March 14, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Marco Morandotti (TUM) - TBA, HFG 611
Tuesday, March 19, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Thursday, March 21, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Matthias Ruf (Universite Libre de Bruxelles) - TBA, HFG 611
Tuesday, March 26, 2019
16:00-17:00
Utrecht Geometry Center Seminar
Christoph Winges (MPIM Bonn) - t.b.a., HFG 611
Thursday, March 28, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Cristian Spitoni (UU) - TBA, HFG 611
Tuesday, April 2, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Thursday, April 4, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Michal Branicki (Edinburgh) - TBA, HFG 611
Tuesday, April 9, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Tuesday, April 16, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Tuesday, April 23, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Tuesday, April 30, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Thursday, May 2, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Patrick Dondl (Universität Freiburg) - TBA, HFG 611
Tuesday, May 7, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611