Math Calendar

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
16:00-17:00
Utrecht Geometry Center Seminar
Guchuan Li (Copenhagen) - t.b.a.
Thursday, June 4, 2020
16:00-17:00
Online, Teams
Applied Mathematics Seminar
Clara Stegehuis (Twente) - Optimal structures in power-law networks

Subgraphs contain important information about network structures and their functions. We investigate the presence of subgraphs in several random graph models with infinite-variance degrees. We introduce an optimization problem that identifies the dominant structure of any given subgraph. The optimizer describes the degrees of the vertices that together span the most likely subgraph and allows us count and characterize all subgraphs.

We then show that this optimization problem easily extends to other network structures, such as local clustering, which expresses the probability that two neighbors of a vertex are connected. The optimization problem is able to find the behavior of clustering in a wide class of random graph models.

 

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
15:30-16:30
CANCELED Applied Mathematics Seminar
Erik Koelink (Radboud University) - TBA, HFG 611
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
Thursday, June 18, 2020
16:00-17:00
ONLINE
Applied Mathematics Seminar
Dalia Terhesiu (Leiden) - TBA
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
15:30-16:30
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
Thursday, July 2, 2020
16:00-17:00
Online
Applied Mathematics Seminar
Thomas Attema (TNO) - TBA, HFG 611
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
Thursday, July 9, 2020
13:00-17:30
Faculty Day
16:00-17:00
Online, Teams
Applied Mathematics Seminar
Souvik Dhara (MiT/Microsoft) - The r-to-p norm of non-negative random matrices
For an n times n matrix A_n, the r → p operator norm is defined as

|| A_n ||_{r→p} := sup_{x\ in R^n, ||x||_r<1 } || A_n x ||_p  for r,p􏰽>=1,

(see PDF: https://surfdrive.surf.nl/files/index.php/s/RNjWDCMREJbYgJE)

For different choices of r and p, this norm corresponds to key quantities that arise in di- verse applications including matrix condition number estimation, clustering of data, and finding oblivious routing schemes in transportation networks. This talk considers r → p norms of symmetric random matrices with nonnegative entries, including adjacency ma- trices of Erdo ̋s-Rényi random graphs, matrices with positive sub-Gaussian entries, and certain sparse matrices. For 1 < p 􏰼 r < ∞, the asymptotic normality, as n → ∞, of the appropriately centered and scaled norm ||An||_{r→p} is established. This is also shown to imply, as a corollary, asymptotic normality of the solution to the lp quadratic maxi- mization problem, also known as the lp Grothendieck problem for p>􏰽 2. Furthermore, a sharp l∞-approximation for the unique maximizing vector in the definition of ||An||_{r→p} is obtained, which may be of independent interest. In fact, the vector approximation result is shown to hold for a broad class of deterministic sequence of matrices having certain asymptotic expansion properties. The results obtained can be viewed as a generalization of the seminal results of Füredi and Komlós (1981) on asymptotic normality of the largest singular value of a class of symmetric random matrices, which corresponds to the special caser=p=2consideredhere. Inthegeneralcasewith1<p􏰼r<∞,thespectral methods are no longer applicable, which requires a new approach, involving a refined convergence analysis of a nonlinear power method and establishing a perturbation bound on the maximizing vector.

This is based on a joint work with Debankur Mukherjee (Georgia Tech) and Kavita Ramanan (Brown University).

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
Tuesday, August 18, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 25, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 1, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 8, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 15, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 22, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Thursday, September 24, 2020
16:00-17:00
HFG 611
Applied Mathematics Seminar
Yves van Gennip (TU Delft) - TBA, HFG 611)
Tuesday, September 29, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 6, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 13, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 20, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 27, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 3, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 10, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 17, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 24, 2020
13:15-15:15
HFG 610
Seminar Differential Geometry - Morse theory
TBA - TBA
15:30-16:00
HFG Library
Institute Tea