Math Calendar

Tuesday, September 25, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Cary Malkiewich (SUNY Binghamton/MPIM Bonn) - The transfer map of free loop spaces
Let R -> A be a map of rings (or ring spectra) and suppose that A is finitely generated projective (or perfect) as an R-module. Then there is a wrong-way "transfer" map on algebraic K-theory, K(A) -> K(R). In particular, when E -> B is a fibration whose fiber F is a finite CW complex, this gives a wrong-way map on Waldhausen's functor A(B) -> A(E). We ask a few fundamental questions about this transfer, and present the beginning of a program to answer these questions using trace methods. Our main result concerns the corresponding transfer in topological Hochschild homology (THH), which is a stable map of free loop spaces LB -> LE. Aside from the insights into algebraic K-theory, these results appear to give us new computational tools for the homology of free loop spaces. This is joint work with John Lind.
Wednesday, September 26, 2018
11:00-12:00
BBG 7.12
Mathematical Physics Seminar
Martijn Kool (UU) - New calculations in Vafa-Witten theory
Abstract: "In the 1990's, Vafa-Witten tested S-duality of N=4 SUSY Yang-Mills theory on a complex algebraic surface by studying modularity of a certain partition function. Recently, a mathematical definition of Vafa-Witten's invariants was given by Tanaka-Thomas. I outline a method for calculating the instanton contribution to these invariants using Mochizuki's theory of algebraic Donaldson invariants. For SU(2), this leads to verifications of Vafa-Witten's original formula. For SU(3), we find a surprising new formula which corrects an error in the physics literature. I discuss refinements of our instanton calculations to virtual \chi_y genus, elliptic genus, and cobordism class, which involves Jacobi forms and Borcherds lifts thereof. Joint with Göttsche."
Tuesday, October 2, 2018
12:00-13:00
MI library
Bring Your Own Lunch
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Jens Forsgaard (Universiteit Utrecht) - t.b.a., HFG 611
Thursday, October 4, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Arjan van der Schaft (RUG) - TBA, HFG 611 (16
Tuesday, October 9, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Álvaro del Pino Gómez (Utrecht University) - t.b.a., HFG 611
Thursday, October 11, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Sonja Hohloch (Universiteit Antwerpen) - TBA, HFG 611 (16
Tuesday, October 16, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Tuesday, October 23, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Cristina Manolache (Imperial College London) - A splitting of the virtual class for genus one stable maps, HFG 611
In order to define intersection theory on spaces with several components of different dimensions one needs to define a "virtual class". I will explain the construction of the virtual class in simple examples and then show how to split this class on components. I will discuss applications to moduli spaces of genus one stable maps.
Thursday, October 25, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Carolin Kreisbeck (UU) - Asymptotic rigidity of layered structures and applications, HFG 611 (16
Tuesday, October 30, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Emmanuel Kowalski (ETH Zürich) - Stories of Kloosterman sums, HFG 611
Kloosterman sums are finite exponential sums which have remarkable
applications in analytic number theory, ranging from diophantine
problems to modular forms and the distribution of primes.

The talk will present the history of the study of these sums and
discuss their properties, including a number of open problems. There
will be a particular emphasis on links with algebraic geometry, and on
distribution problems for Kloosterman sums.
Tuesday, November 6, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Rosa María Miró i Roig (Universitat de Barcelona) - t.b.a., HFG 611
Thursday, November 8, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Dominik Engl (UU) - Gamma-convergence for incompressible strings and rods, HFG 611 (16
Tuesday, November 13, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Jonathan Belletête (CEA Saclay) - A pseudo-fusion category from Temperley-Lieb algebras, HFG 611
Two dimensional conformal field theories, appearing in many branches of physics, can be ( partially ) encoded into a category of representations of some vertex operator algebra; there the tensor product of representations encodes the interactions of the particles in the theory. If these interactions are sufficiently well-behaved, then this will be a Fusion category; these appear in many areas of mathematics, for instance in the representation theory of Hopf algebras, in the construction of 3D topological invariants, etc. The question is then: what if the interactions are not well-behaved? One can show easily that the defining axioms of a Fusion category are then no longer satisfied, but how should they be replaced?

The Temperley-Lieb algebras are an infinite family of associative algebras indexed by two parameters: a positive integer N and a complex number q. Physicists have argued that these algebras can be used to build 2d conformal field theories, in particular ones where the interactions are well-behaved, and ones where they are not. I will show how their categories of representations can be turned into proper tensor categories; I will discuss how these can be understood as Fusion categories in certain cases, and what happens when they can't.

Based on joint work with Yvan Saint-Aubin.
Thursday, November 15, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Alden Waters (RUG) - Inverse Problems for Coupled Systems of Wave Equations, HFG 611 (16
Tuesday, November 20, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
Utrecht Geometry Center Seminar
Georg Oberdieck (MIT/Bonn)- t.b.a., HFG 611
Thursday, November 22, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Matthias Schlottbom (U Twente) - TBA, HFG 611 (16
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) - t.b.a., HFG 611
Thursday, November 29, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Chris Stolk (UvA) - TBA, HFG 611 (16
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 611 (16
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)- t.b.a., HFG 611
Thursday, December 13, 2018
16:00-17:00
Utrecht
Complex Systems Seminar
Bob Rink (UvA) - TBA, HFG 611 (16
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
Tuesday, January 15, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Tuesday, January 22, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - 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 611 (16
Tuesday, February 5, 2019
16:00-17:00
Utrecht Geometry Center Seminar
t.b.a. - t.b.a., HFG 611
Thursday, February 7, 2019
15:30-16:30
Staff colloquium
Hector Pasten (PUC, Chile) - t.b.a., t.b.a.
Thursday, February 14, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Felix Beckebanze (UU) - TBA, HFG 611 (16
Thursday, March 7, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Caterina Zeppieri (Universität Münster) - TBA, HFG 611 (16
Thursday, March 14, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Marco Morandotti (TUM) - TBA, HFG 611 (16
Thursday, March 21, 2019
16:00-17:00
Utrecht
Complex Systems Seminar
Matthias Ruf (Universite Libre de Bruxelles) - TBA, HFG 611 (16