Math Calendar

Thursday, July 9, 2020
13:00-17:30
Faculty Day
16:00-17:00
Online, Teams
Updated
Applied Mathematics Seminar

The talk concerns critical behavior of percolation on finite random networks with heavy-tailed degree distribution. In a seminal paper, Aldous (1997) identified the scaling limit for the component sizes in the critical window of phase transition for the Erdos-Renyi random graph. Subsequently, there has been a surge in the literature  identifying two universality classes for the critical behavior depending on whether the asymptotic degree distribution has a finite or infinite third moment.  

In this talk, we will present a completely new universality class that arises in the context of degrees having infinite second moment. Specifically, the scaling limit of the rescaled component sizes is different from the general description of multiplicative coalescent given by Aldous and Limic (1998). Moreover, the study of critical behavior in this regime exhibits several surprising features that have never been observed in any other universality classes so far.

Friday, July 10, 2020
16:00-17:00
Zoom
Friday Fish Seminar
Daniele Sepe (Universidade Federal Fluminense) - Symplectic, Contact, Poisson, Jacobi, Affine, Projective

While contact geometry is often described as the odd-dimensional analogue of symplectic geometry, Arnol'd pointed out that the relation between these two geometries is analogous to that between affine and projective geometries. A natural (vague!) question is to investigate the extent to which this analogy extends to the degenerate versions of symplectic and contact structures, namely Poisson and Jacobi geometries.

The aim of this talk is to attempt to formalise the above question and to illustrate the intimate relation between these six geometries through a few specific problems, including isotropic realisations and Poisson/Jacobi manifolds of compact types. The talk is based on joint work with María Amelia Salazar, and on ongoing joint work with Camilo Angulo and María Amelia Salazar.

Tuesday, July 14, 2020
15:30-16:00
HFG Library
Institute Tea
Wednesday, July 15, 2020
11:00-12:00
online
Master thesis defense
Abe ten Voorde - Cyclic algebras in local fields arising from elliptic curves

Written under supervisionof Dr. Lennart Meier

Abstract
Richard Brauer introducedthe concept of the Brauer group of a field K to classify central simplealgebras over K. An important example of a central simple algebra is a cyclicalgebra which we can associate to a cyclic Galois extension over K and anelement of the multiplicative group of K.


In this thesis, we study local fields and determine which elements of theBrauer group can be reached if we restrict ourselves to the subgroup of K* ofdiscriminants of elliptic curves over K. We show that essentially any expectedelement of the Brauer group can be reached. Using local class field theory wealso show that the answer differs when we look at elliptic curves over the ringof integers of a local field over the 2- and 3-adic numbers.


 MSTeamsCode: q4lin3v 
Friday, July 17, 2020
13:00-14:00
online
Master thesis defense
Kieran Power - g-Measures in the study of random beta-transformations

Written under  the supervision of Dr. Karma Dajani, with Dr. SjoerdDirksen as second reader.

Abstract
 We revisit the idea of the random beta-transformation fornon-integral beta>1. This is a measurable dynamical system motivated by thestudy of number expansions in non-integer bases, which behave very differentlyto the usual expansions in integer bases. During this presentation we willdiscuss these expansions, which motivate the definition of the randombeta-transformation, which we provide and discuss. We then provide a basicexposition of the theory of g-measures, by first motivating their definition,and then discussing some of their unexpected links to thermodynamical formalism,culminating in Ruelle's Operator Theorem. Finally we use the machinery ofg-measures to construct a new family of strongly mixing invariant measures forthe random beta-transformation for certain algebraic beta.

 

The team can be joined using the following link: https://teams.microsoft.com/l/meetup-join/19%3ameeting_MDQzZDUxYTktM2U1Zi00YzFjLWE1NDktMzM1OGYwYzFmOTdh%40thread.v2/0?context=%7b%22Tid%22%3a%22d72758a0-a446-4e0f-a0aa-4bf95a4a10e7%22%2c%22Oid%22%3a%22fb36163f-a37b-418c-a69b-b6b41a1b6733%22%2c%22IsBroadcastMeeting%22%3atrue%7d
16:00-17:00
Zoom
Friday Fish Seminar
Ralph Klaasse (ULB) - TBA
TBA
Tuesday, July 21, 2020
15:30-16:00
HFG Library
Institute Tea
Friday, July 24, 2020
16:00-17:00
Zoom
Friday Fish Seminar
María Amelia Salazar (Universidade Federal Fluminense) - TBA
TBA
Tuesday, July 28, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 4, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 11, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 18, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, August 25, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 1, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 8, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 15, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, September 22, 2020
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
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 6, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 13, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 20, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, October 27, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 3, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 10, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 17, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, November 24, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, December 1, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, December 8, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, December 15, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, December 22, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, December 29, 2020
15:30-16:00
HFG Library
Institute Tea
Tuesday, January 5, 2021
15:30-16:00
HFG Library
Institute Tea