Tuesday, March 9, 2021
17:00-18:30
On Zoom
Utrecht Geometry Centre Seminar
Mingcong Zeng - From exotic spheres to equivariant homotopy
In 1956, Milnor discovered that there are several smooth structures on the 7-spheres that are not diffeomorphic to the standard one.  In 1963, Kervaire and Milnor provided a method of counting the number of smooth structures on spheres of dimension greater than 4.

In this talk, I will start with their results, and talk about how this geometric problem was transformed into a problem in homotopy theory, and discuss how equivariant homotopy comes into play. Finally, I will talk about some recent results with my collaborators on equivariant homotopy and some confusing problems I am thinking about.



Website of the seminar: http://utrechtgeometrycentre.nl/ugc-seminar/ 
Zoom details will be sent by email to the staff and student mailing lists a few days before the event. 
Wednesday, March 10, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Thursday, March 11, 2021
16:00-17:00
ZOOM
Applied Mathematics Seminar --Oxana Manita (TU/e) Universal Approximation in Neural networks with dropout.
Overfitting is a common phenomenon in training neural networks -- the model learns the training data too well, but doesn’t perform well on real data. One of the regularization techniques used to deal with this issue is so-called dropout: each weight is given a random binary filter. In this talk I am going to discuss the approximation properties of dropout networks. Two versions of dropout networks are considered – networks with random output and networks with deterministic output obtained by replacing filters by their expected values. The latter is the commonly used in practice mode of operation. It turns out that both types of networks preserve approximation properties. Moreover, for a given function, one can construct a network that approximates it well in both modes simultaneously. (Joint work with M. Peletier. J. Portegies, J. Sanders and A. Senen-Cerda)
Friday, March 12, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, March 17, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Tuesday, March 23, 2021
17:00-18:00
On Zoom
Utrecht Geometry Centre Seminar
Martijn Kool - Proof of a Magnificent Conjecture

Solid partitions are piles of boxes in the corner of a 4-dimensional room. Their enumeration is a mystery since MacMahon proposed an incorrect formula around 1916. Motivated by super-Yang-Mills theory on (complex) 4-dimensional affine space, Nekrasov recently assigned a measure to solid partitions and proposed a conjectural formula for their weighted enumeration.

We give a geometric definition of this measure using the Hilbert scheme of points on 4-dimensional affine space. Although this Hilbert scheme is very singular and has “higher obstruction spaces”, we can use recent work of Oh-Thomas to localise our invariants and prove Nekrasov’s conjecture. Joint work with J. V. Rennemo.

 

Website of the seminar: http://utrechtgeometrycentre.nl/ugc-seminar/
Zoom details will be sent by email to the staff and student mailing lists a few days before the event.

Wednesday, March 24, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, March 26, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, March 31, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, April 2, 2021
14:00-17:00
Zoom
Dutch Differential Topology and Geometry Seminar
Oleg Lazarev - TBA
TBA

Zoom details can be found in the website of the seminar: https://www.few.vu.nl/~trt800/ddtg.html
Wednesday, April 7, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, April 9, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, April 14, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, April 21, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, April 23, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, April 28, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Thursday, April 29, 2021
16:00-17:00
ZOOM
Applied Mathematics Seminar --Anastasia Borovykh (Imperial College London)
Wednesday, May 5, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, May 7, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, May 12, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, May 19, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, May 21, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, May 26, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, June 2, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, June 4, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, June 9, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, June 16, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Friday, June 18, 2021
10:00-12:00
Seminar "Logarithmic and geometry and log Gromov-Witten theory" (online, two-weekly).
If you want to participate and wish to receive further information,please contact Marta at m.pieropan@uu.nl
Wednesday, June 23, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, June 30, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, July 7, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, July 14, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, July 21, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, July 28, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, August 4, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, August 11, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, August 18, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, August 25, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html 

Wednesday, September 1, 2021
15:15-17:00
Microsoft Teams
Reading seminar "Arithmetic of K3 surfaces" (online)

The seminar will be held online via Microsoft Teams. You can join the team by using the code bahj12a. 

The (preliminary) schedule for the seminar can be found on https://webspace.science.uu.nl/~karem001/K3sem.html