Mathematical Institute Calendar

Monday, April 15, 2024

09:15-17:30

KBG Atlas

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

see description

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

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

see description

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

Thursday, April 18, 2024

09:15-17:30

KBG Atlas

10:30-11:30

BBG 017

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

Tuesday, April 23, 2024

12:00-13:00

HFG 610

16:00-17:00

HFG 611

TBA

Seminar webpage https://utrechtgeometrycentre.nl/ugc-seminar/

Seminar webpage https://utrechtgeometrycentre.nl/ugc-seminar/

Wednesday, April 24, 2024

Thursday, April 25, 2024

16:00-17:00

HFG 611

Friday, April 26, 2024

15:00-16:00

Minnaert 0.13

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

Thursday, May 16, 2024

16:00-17:00

HFG 611

Tuesday, May 28, 2024

16:00-17:00

HFG 611

Thursday, June 6, 2024

16:00-17:00

HFG 611

Friday, June 7, 2024

11:00-16:00

Thursday, June 20, 2024

Thursday, June 27, 2024

16:00-17:00

HFG 611

Thursday, September 5, 2024