Math Calendar

Tuesday, February 18, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Sebastiaan Smeenk - Existence and abundance of Morse functions
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Victoria Cantoral Farfán (KU Leuven) - Fields of definition of elliptic fibrations on covers of certain extremal rational elliptic surfaces



K3 surfaces have been extensively studied over the past decades for several reasons. For once, they have a rich and yet tractable geometry and they are the playground for several open arithmetic questions. Moreover, they form the only class which might admit more than one elliptic fibration with section. A natural question is to ask if one can classify such fibrations, and indeed that has been done by several authors, among them Nishiyama, Garbagnati and Salgado. The particular setting that we were interested in studying is when a K3 surface arises as a double cover of an extremal rational elliptic surface with a unique reducible fiber. This K3 surface will have a non-symplectic involution τ fixing two smooth Galois-conjugate genus 1 curves. In this joint project we determine the fields of definition of the different fibrations on this K3 surface, depending on τ. Moreover, we determine as well the field of definition of the Mordell–Weil group of each fibration. This is a joint work with A. Garbagnati, C. Salgado, A. Trbovi ́c and R. Winter.

Thursday, February 20, 2020
13:30-14:30
MINN 0.16
William (Bill) Mance
Normal numbers for the Cantor series expansions and possible applications in algebraic geometry

Abstract: We will discuss basic properties of normal numbers for theCantor series expansions and a recent result of D. Airey and B. Mance.

Using ideas introduced in this paper, it maybe possible to show that information about algebraic varieties is encoded inthe structure of sets of normal numbers. We will outline this idea and thebarriers one may encounter in finishing it.

16:00-17:00
Applied Mathematics Seminar
Stefanie Sonner (Radboud Universiteit) - Stabilization by boundary noise
Title:
Stabilization by boundary noise: a Chafee-Infante equation with dynamical boundary conditions

Abstract:
The stabilization of parabolic PDEs by multiplicative noise is a well know phenomenon that has been studied extensively over the past decades. However, the stabilizing effect of a noise that acts only on the boundary of a domain had not been investigated so far.
As a first model case we consider the Chafee-Infante equation with dynamical boundary conditions and analyze whether a linear multiplicative Itô noise on the boundary can stabilize the equation. In particular, we show that there exists a finite range of noise intensities that imply the exponential stability of the zero steady state. Our results differ from previous works on stabilization, where the noise acts inside the domain, and stabilization typically occurs for an infinite range of noise intensities.
This is joint work with Klemens Fellner, Bao Q. Tang (University of Graz) and Do D. Thuan (Hanoi University of Science and Technology).
Monday, February 24, 2020
13:15-15:00
HFG 610
Master Seminar Number Theory `Expander graphs'
Evie Roebroek - Expansion in graphs I
15:15-17:00
610,
MSc Seminar Algebraic Topology - Bram Buiting
Existence of Stiefel-Whitney classes
Tuesday, February 25, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Santiago Quintero - Cell attachments and critical points of Morse functions
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. - t.b.a.
Wednesday, February 26, 2020
16:15-17:15
Academy Bldg
Thesis defense
Francesco Cattafi - A general approach to almost structures in geometry
Thursday, February 27, 2020
16:00-17:00
Applied Mathematics Seminar
Agnes Lamacz (University of Duisburg-Essen) - Overdamped limit of the Vlasov-Fokker-Planck equation
Titel: Overdamped limit of the Vlasov-Fokker-Planck equation: A
variational approach

Abstract:
Coarse-graining is the procedure of approximating a complex system by a simpler or lower-dimensional one, often in some limiting regime. Coarse-graining limits are by nature singular limits. Therefore rigorous proofs of such limits typically hinge on exploiting certain structural features of the equations such as variational-evolution structures, which for instance are present in gradient flows.

In the first part of the talk we introduce and discuss such a variational structure arising from the theory of large deviations for stochastic processes. We show how in systems, which are characterized by a large deviation rate functional, passing to a limit is facilitated by the dual formulation of the rate functional, in a way that interacts particularly well with coarse-graining. Being closely related to classical variational methods for gradient flows, our approach is also applicable to systems with non-dissipative effects. As an example we apply the technique to derive the large friction (overdamped) limit of the Vlasov-Fokker-Planck equation.

In the second part of the talk we show how the large deviation rate functional can be used to quantify the approximation error.

The talk is based on a joint work with M. Hong Duong, Mark A. Peletier, Andre Schlichting and Upanshu Sharma.
Monday, March 2, 2020
12:45-13:45
Academy Bldg
Thesis defense
Lauran Toussaint- Contact Structures & Codimension-one Symplectic Foliations
13:15-15:00
HFG 610
Master Seminar Number Theory `Expander graphs'
Onno van Zomeren - Expansion in graphs II; Random walks I
15:15-17:00
610,
MSc Seminar Algebraic Topology - Jaco Ruit
Euler classes and the Thom isomorphism
Tuesday, March 3, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Aaron Gootjes-Dreesbach - Homotopy type of manifolds
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Markus Land - Regensburg/Copenhagen
Thursday, March 5, 2020
16:00-17:00
MIN 2.01
The Utrecht Mathematical Colloquium
Margherita Disertori (Bonn) - A model for liquid crystals in two and three dimensions

In 1949, L. Onsager proposed a statistical theory for a system of elongated molecules interacting via repulsive short-range forces. Onsager's theory predicted the existence at intermediate densities of a nematic liquid crystal phase, in which the distribution of orientations of the particles is anisotropic, 

while the distribution of the particles in space is homogeneous and does not exhibit the periodic variation of densities that characterizes solid crystals (periodicity in all space dimensions). 

I will introduce a simplified model for this problem consisting of long rods (in two dimensions) and anisotropic plates (in three dimensions), characterized by purely hard core interactions and a finite number of allowed orientations. 

For this model I will review some results/conjectures. This is a joint work with A. Giuliani and I. Jauslin

Monday, March 9, 2020
13:15-15:00
HFG 610
Master Seminar Number Theory `Expander graphs'
Erin van der Kamp - Random walks II
15:15-17:00
610,
MSc Seminar Algebraic Topology - Wilmer Smilde
Poincaré duality and the Euler characteristic
Tuesday, March 10, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Pepijn de Maat - Reeb theorem and Lefschetz hyperplane theorem
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Maria Ángeles García-Ferrero (MPI Leipzig) - t.b.a.
Monday, March 16, 2020
13:15-15:00
HFG 610
Master Seminar Number Theory `Expander graphs'
t.b.a. - Random walks III
15:15-17:00
610,
MSc Seminar Algebraic Topology - Max Blans
Chern classes and their relation to differential geometry
Tuesday, March 17, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Stan Wever - Cobordism category and Morse number
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Quoc P. Ho (IST Austria) - t.b.a.
Thursday, March 19, 2020
16:00-17:00
Applied Mathematics Seminar
Verena Schamboeck (UvA) - TBA, HFG 611
Friday, March 20, 2020
11:00-17:00
TBA
InterCity Number Theory Seminar
Monday, March 23, 2020
13:15-15:00
HFG 610
Master Seminar Number Theory `Expander graphs'
David Hokken - Random walks and expansion
15:15-17:00
610,
MSc Seminar Algebraic Topology - Ryan Quinn
Chern numbers and Pontryagin numbers
Tuesday, March 24, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Nina Rutten - Handle attachments
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Emma Brakkee (Amsterdam) - t.b.a.
Thursday, March 26, 2020
15:30-16:30
KBG Atlas
The 6th Daniel Kan Memorial Lectures
Mikhail Kapranov (Kavli Institute, Kashiwa, Japan) - Factorization algebras in algebraic geometry I
16:00-17:00
Applied Mathematics Seminar
Yves van Gennip (TU Delft) - TBA, HFG 611
Friday, March 27, 2020
11:00-12:00
KBG Cosmos
The 6th Daniel Kan Memorial Lectures
Mikhail Kapranov (Kavli Institute, Kashiwa, Japan) - Factorization algebras in algebraic geometry II
13:00-14:00
MIN 202
The 6th Daniel Kan Memorial Lectures
Mikhail Kapranov (Kavli Institute, Kashiwa, Japan) - Factorization algebras in algebraic geometry III
Monday, March 30, 2020
13:15-15:00
HFG 610
Master Seminar Number Theory `Expander graphs'
Ariane Blok - Laplace operators and expansion in Cayley graphs
Tuesday, March 31, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
Luuk Visscher - Rearrangement of cobordisms
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Wouter van Limbeek - t.b.a.
Tuesday, April 7, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG611
Utrecht Geometry Center Seminar
t.b.a - t.b.a.
Tuesday, April 14, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a - t.b.a.
Thursday, April 16, 2020
16:00-17:00
Applied Mathematics Seminar
Thang Huynh (RWTH Aachen University) - TBA, HFG 611
Tuesday, April 21, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
BBG017
Utrecht Geometry Center Seminar
t.b.a - t.b.a.
Thursday, April 23, 2020
16:00-17:00
Applied Mathematics Seminar
Fernando E. Rosas (Imperial College London) - TBA, HFG 611
Tuesday, April 28, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Ailsa Keating (Cambridge) - t.b.a.
Thursday, April 30, 2020
16:00-17:00
Applied Mathematics Seminar
Dalia Terhesiu (Leiden) - TBA, HFG 611
Tuesday, May 5, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, May 12, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Thursday, May 14, 2020
16:00-17:00
Applied Mathematics Seminar
Sjoerd Dirksen (UU) - TBA, HFG 611
Tuesday, May 19, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Thursday, May 21, 2020
16:00-17:00
Applied Mathematics Seminar
Theresa Lange (TU Berlin) - TBA, HFG 611
Tuesday, May 26, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, June 2, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, June 9, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Thursday, June 11, 2020
16:00-17:00
MIN 2.01
The Utrecht Mathematical Colloquium
Bill Symes (Rice) - TBA
Tuesday, June 16, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, June 23, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Thursday, June 25, 2020
16:00-17:00
Applied Mathematics Seminar
Alexandre Gaudilliere (Marseille) - TBA, HFG 611
Tuesday, June 30, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, July 7, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, July 14, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, July 21, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, July 28, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 4, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 11, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea