Monday, April 15, 2024
09:15-17:30
KBG Atlas
Conference “(∞,n)-Categories and their applications”
For talk titles, abstracts,and time slots, you can find a detailed schedule on our conference webpage https://sites.google.com/view/inftyncategories.
11:00-12:00
BBG-005
MSc presentation
Veerle van den Hurk - Towards Integrated Blockbased Cyclic Rostering for Railway Crew

Supervisors: Sjoerd Dirksen, Marjan van den Akker, Egon van denBroek and Erwin Abbink (NS)

 Abstract: We examine the ability to form cyclicrosters for conductors and train drivers using blocks (duty templates) insteadof duties, while respecting labour regulations. These blocks take up more timethan actual duties, but have no content yet. This first difference complicatesthe use of forbidden or desired patters of early/late/night shifts in ourmodel, as is usually used in literature. However, not knowing the content ofthe blocks makes some of the roster rules, that are usually taken into account,redundant. We propose an integrated model for this Cyclic Crew RosteringProblem, in which days off and blocks are assigned to the roster of a wholecrew base simultaneously. We model the problem as an assignment problem andevaluate its performance on real-life instances of Netherlands Railways (NS).It turns out that it is possible to generate feasible rosters from theconsidered blocks when taking labour regulations into account. However, theseresulting rosters are unattractive to crew members. When adding constraintsregarding the balancing of workload over the weeks, the problem gets harder tosolve for large crew bases.

Tuesday, April 16, 2024
09:15-17:15
Ruppert Paars
Conference “(∞,n)-Categories and their applications”
For talk titles, abstracts,and time slots, you can find a detailed schedule on our conference webpage https://sites.google.com/view/inftyncategories.
16:00-17:00
HFG 611
Number Theory Talk
Jakob Glas (IST Austria) - Canonical singularities on moduli spaces of rational curves via the circle method
I will explain how methods from analytic number theory can shed light on problems in algebraic geometry. In particular, I will show how a suitable version of the circle method can be used to show that moduli spaces of rational curves contained in a smooth hypersurface have at worst canonical singularities under suitable assumptions on the degrees and the dimensions.
Wednesday, April 17, 2024
09:00-12:45
KBG Pangea
Conference “(∞,n)-Categories and their applications”
For talk titles, abstracts,and time slots, you can find a detailed schedule on our conference webpage https://sites.google.com/view/inftyncategories.
Thursday, April 18, 2024
09:15-17:30
KBG Atlas
Conference “(∞,n)-Categories and their applications”
For talk titles, abstracts,and time slots, you can find a detailed schedule on our conference webpage https://sites.google.com/view/inftyncategories.
10:30-11:30
BBG 017
AG Seminar talk
Andrea Ricolfi - The motive of the Hilbert scheme of points
Abstract: The geometry of Hilbert schemes of points is largely unknown, or known to be pathological in a precise sense. This should in principle make most (naive) invariants essentially inaccessible. In this talk we explain how to obtain a closed formula for the generating function of the motives (classes in the Grothendieck ring of varieties) of Hilbert schemes of points Hilb(X,d) for X a smooth variety of arbitrary dimension, and for fixed number of points d < 9. Work in progress with M. Graffeo, S. Monavari and R. Moschetti.
Friday, April 19, 2024
09:15-14:30
Ruppert Wit
Conference “(∞,n)-Categories and their applications”
For talk titles, abstracts,and time slots, you can find a detailed schedule on our conference webpage https://sites.google.com/view/inftyncategories.
Tuesday, April 23, 2024
12:00-13:00
HFG 610
Freudenthal topology seminar
Léonard Guetta - TBA
16:00-17:00
HFG 611
MI talk
Dirk van Bree - TBA
Wednesday, April 24, 2024
12:00-13:00
MI library
BYOL
15:15-16:45
Active Bystander Training
Internal training, registration required
Thursday, April 25, 2024
16:00-17:00
HFG 611
Applied Math Seminar
Andrei Caragea (MIDS, Katholische Universität Eichstätt)
Title: Hierarchical Riesz exponential bases and Chebotarëv’s theorem
Abstract: A discrete frequency set Λ ⊂ R is called Riesz spectral for some finite measure set S ⊂ R if the family {exp(2πiλ(.)) : λ ∈ Λ} is a Riesz basis (of exponentials) for L^2(S). This can be seen as a generalization of the notion of a Fourier basis (e.g., Z is Riesz, actually orthogonally, spectral for [0, 1]). The understanding of which sets S admit Riesz spectra is far from complete. One of the major results of the last decade in this direction is due to Kozma and Nitzan and states that every finite union of bounded intervals does indeed admit a Riesz spectral set. Inspired by this and the work of Pfander, Revay and Walnut, we explore the notion of hierarchical Riesz bases for finite unions of intervals. Namely, given intervals I_1, I_2, . . . , I_L, when can one find discrete frequency sets Λ_1, Λ_2, . . . , Λ_L, such that for each index subset J ⊂ {1, 2, . . . ,L} we have that the union of Λ_j for j∈J is Riesz spectral for  the union of I_j, j∈J . We present some partial results towards settling this question and the connection to Chebotarëv’s theorem on invertible Fourier submatrices.
Friday, April 26, 2024
14:00-16:30
DDT&G
Luciana Basualdo Bonatto – TBA
15:00-16:00
Minnaert 0.13
MSc presentation Anouk Eggink- Diophantine Maps

Supervisor: Gunther Cornelissen

Second reader: Valentijn Karemaker

 

Abstract:

My thesis is about Hilbert's tenth problemand Diophantine maps. Hilbert's tenth problem asks for an algorithm that givena polynomial equation with coefficients in the integer decides whether or notthis equation has a solution over the integers. In 1970 it has been proven thatsuch an algorithm does not exist. But mathematicians did not stop here, sincewe can easily generalize this problem: Does there exist an algorithm that,given a system of polynomial equations with coefficients in some ring R_0, decideswhether or not it has a solution in some ring R that contains R_0? The maintool that is used to get negative answers for various rings is to reduce theproblem to the integers. I have formalized this type of reduction viaDiophantine maps, which I will introduce in my talk. 

Then we will move to Hilbert's tenthproblem over some noncommutative rings. In my thesis I have proven severalresults about Hilbert's tenth problem over the twisted polynomial rings andvariants thereof. I also looked at differential polynomials and its divisionring of fractions. In my talk I will introduce some of these rings and some ofthe results I have proven.

I will assume knowledge of (polynomial)rings and fields and some knowledge of logic.

Thursday, May 2, 2024
16:00-17:00
HFG 611
Applied Math Seminar
János Flesch (Maastricht) for May 2, Equilibrium in stochastic games with Borel measurable evaluations
Thursday, May 16, 2024
16:00-17:00
HFG 611
Applied Math Seminar
Maosheng Yang (TU Delft)
Title: TBA
Abstract: TBA
Tuesday, May 28, 2024
16:00-17:00
HFG 611
UGC Seminar
Raymond Cheng (Hannover) - TBA
Thursday, June 6, 2024
16:00-17:00
HFG 611
Applied Math Seminar
Bernhard von Stengel (London School of Economics)
Friday, June 7, 2024
11:00-16:00
Mark Kac seminar in mathematical physics and probability
Yvan Velenik (U Geneva) and F. den Hollander (UL)
Thursday, June 20, 2024
16:00-17:00
HFG 611
Applied Math Seminar
Gergely Bodo (UvA)
Thursday, June 27, 2024
16:00-17:00
HFG 611
Applied Math Seminar
Francesca Bartolucci (TU Delft)
Title : TBA
Abstract: TBA
Thursday, September 5, 2024
16:00-17:00
MI talk Yuri Kuznetsov
Title: Recent progress in the numerical bifurcation analysis of delay differential equations
Abstract: TBA