## tba

Zoom Meeting-ID: 994 2805 4844

For passcode please contact Christian Kaiser (kaiser@mpim...).

## Perverse Sheaves and Morse Theory

Zoom Meeting-ID: 994 2805 4844

For passcode please contact Christian Kaiser (kaiser@mpim...).

## Formalism of Perverse Sheaves

Zoom Meeting-ID: 994 2805 4844

For passcode please contact Christian Kaiser (kaiser@mpim...).

## Maxima of a Random Model of the Riemann Zeta Function over Intervals of Varying Length

Zoom Meeting ID: 919 6497 4060

For password see the email or contact Pieter Moree (moree@mpim...).

## The Yang Baxter equation: origins and connection to symmetric functions

Please note the time!

For meeting ID and passcode please contact Christian Kaiser (kaiser@mpim...).

## Pair correlation of sequences: metric results and a modified additive energy.

The uniform distribution of a sequence $\{x_n\}_{n\geq 1}$ measures the pseudo-random behavior at a global scale. At a more localized scale, we can study the pair correlation for sequences in the unit interval. Pseudo-random behavior with respect to this statistic is called Poissonian behavior.

## tba

The seminar is virtual via Zoom.

## tba

Please note the time.

## tba

The seminar is virtual via Zoom.

## tba

Meeting ID: 916 5855 1117

Password: as before.

Contact: Aru Ray and Tobias Barthel.

## Topological rigidity and low dimensional topology

## Surgery Theory and 4-manifolds

it to specific questions in four manifold topology.

Meeting ID: 916 5855 1117

Password: as before.

## An introduction to surgery

## Geometry without spaces: a hyperbolic parable

We revisit old ideas that are shared by functional analysts and logicians alike, in order to do hyperbolic geometry without bothering with practicalities such as spaces or dimension.

Our main interest will be the interplay between (real or complex) hyperbolic geometry and group representations.

## Fibered periods and modularity of conifold fibers

This is a progress report on my work with Kilian Bönisch and Albrecht Klemm.

We study explicit modular fibrations of rigid Calabi-Yau manifolds occurring as fibers in hypergeometric families similar to the one constructed from the mirror quintic.

Zoom Meeting ID: 919 6497 4060

For password see the email or contact Pieter Moree (moree@mpim...).

## Skein Algebras and Categories

In this talk I will discuss how to extend skein algebras into skein categories and interpret these skein categories as factorisation homology theories before returning again to algebras.

Meeting ID: 916 5855 1117

Password: as before.

Contact: Arunima Ray, Tobias Barthel

Seminar page: https://nextcloud.mpim-bonn.mpg.de/s/Tq9bsCWsAJrRiNk

## Arf invariants in low dimensions

I will briefly discuss some work in progress regarding a relationship between several different mod 2 invariants in dimensions 2, 3, and 4. In particular, I will relate the Arf invariant of a knot, the Arf invariant of a characteristic surface, the Rochlin invariant of a homology sphere, and the Kirby-Siebenmann invariant of a 4-manifold.

Meeting ID: 916 5855 1117

Password: as before.

Contact: Arunima Ray, Tobias Barthel

## On the negative Pell equation

Zoom Meeting ID: 919 6497 4060

For password see the email or contact Pieter Moree (moree@mpim...).

How often does the ring of integers of a real quadratic field have a unit with norm -1? In 1995

Peter Stevenhagen proposed a precise conjectural asymptotic formula describing how many such real quadratic fields should be out there when counted by discriminant. I will discuss a joint upcoming work with Peter Koymans where we establish Stevenhagen's conjecture.

## Exponential sums over primes in short intervals, arithmetic progressions and zeros of the Riemann zeta function

Zoom Meeting ID: 919 6497 4060

For password see the email or contact Pieter Moree (moree@mpim...).

© MPI f. Mathematik, Bonn | Impressum & Datenschutz |