[Facets-of-complexity] Invitation to Monday's Lecture & Colloquium Nov.8 !

["I.Brunke" <i.brunke@fu-berlin.de>]

Dear all,

next Monday's Lecture and Colloquium will take place November 8 at TU Berlin.
You all are cordially invited!


Please note Corona restrictions !  - See rules in detail below !

Location:

Room MA 041 - Ground Floor
Technische Universität Berlin
Institut für Mathematik
Straße des 17. Juni 136
10623 Berlin

Monday's Lecture: Manfred Scheucher (Technische Universität Berlin)

Time: Monday, November 8 - 14:15 h

Title: Erdős-Szekeres-type Problems on Planar Point Sets

Abstract:

In 1935, Erdős and Szekeres proved that, for every positive integer k, every sufficiently large point set contains a "k-gon", that is, a subset of k points which is the vertex set of a convex polygon. Their theorem is a classical result in both, combinatorial geometry and Ramsey theory, and motivated a lot of further research including numerous modifications and extensions of the theorem. In this talk we discuss some results and methods that played an essential role in the study of k-gons and the variant of "k-holes".


Coffee Break

Monday's Colloquium: Davide Lofano (Technische Universität Berlin)

Time: Monday, November 8 - 16:00 h s.t.

Title: Hadamard Matrix Torsion

Abstract:

After a brief overview about torsion in homology and examples of complexes with small torsion and few vertices we will focus our attention on a particular series of examples. In particular, we will construct a series HMT(n) of 2-dimensional simplicial complexes with huge torsion, |H_1(HMT(n))|=|det(H(n))|=n^(n/2), where the construction is based on the Hadamard matrices H(n) and they have linearly many vertices in n. Our explicit series improves a previous construction by Speyer, narrowing the gap to the highest possible asymptotic torsion growth achieved by Newman via a randomized construction.


___________

Corona access rules accordingly:

Please observe the current Corona safety constraints:

3G access rule - a medical or FFP2 mask must be worn!
See https://www.fu-berlin.de/en/sites/coronavirus/faq/studium/3g/

Please bring a proof of your vaccination status or test by a certified unit, as well as a photo-ID.

We will regularly open the windows for fresh air.
Please choose your clothing accordingly!

For tracking the contacts in case of an infection, we use a.nwesen.de.
See https://anwesende.imp.fu-berlin.de/

There is a QR-code at every place, which you can scan with your smartphone.


You all are cordially invited!

Virenfrei. www.avast.com