2021 Mar 15

4:00pm to 6:00pm

2020 Dec 09

# Logic Seminar - Jan Dobrowolski

11:15am to 1:00pm

## Location:

https://huji.zoom.us/j/82821066522?pwd=aVJnTkxBYktycHdzNFN5WDV0R2FkZz09
Sets, groups, and fields definable in vector spaces with a bilinear form.

Abstract:
There is a long history of study of algebraic objects definable in classical mathematical structures.
As a prominent example, by results of Weil, Hrushovski, and van den Dries, it is known that the groups definable in an algebraically closed field K are precisely the algebraic groups over K, and the only infinite field definable in K is the field K itself.
2021 Jan 21

# Colloquium: Cornelius Greither (Bundeswehr University Munich) — a short panoramic tour of some zeta functions

2:30pm to 3:30pm

One might say that there exist zeta functions of three kinds: the very well-known ones (whose stock example is Riemann's zeta function); some less familiar ones; and at least one type which has been totally forgotten for decades. We intend to mention instances of all three types. The first type is important, if not predominant, in algebraic number theory, as we will try to illustrate by (very few) examples. As examples of the second type we will discuss zeta functions of finite groups.
2021 Jan 20

# Analysis Seminar: Dirk Hundertmark (Karlsruhe) "Quantum Systems at the Brink: Helium"

12:00pm to 1:00pm

## Location:

Zoom

Title: Quantum Systems at the Brink: Helium

Abstract: Perturbation theoryworks well for the the discrete spectrum below the essential spectrum. Whathappens if a parameter of a quantum system is tuned in such a way that abound state energy (e.g. the ground state energy) hits the bottom of theessential spectrum? Does the eigenvalue survive, i.e., the correspondingeigenfunction stays $L^2$, or does it dissolve into the continuumenergies?

2020 Dec 24

# Basic Notions: Ari Shnidman "Randomness in arithmetic: class groups."

4:00pm to 5:15pm

## Location:

Zoom
For every number fieldK, there is a finite abelian group C called the
class group, which serves as an obstruction to unique factorization.
Since Gauss, number theorists have tried to understand questions such
as how often is C trivial, or how often C contains an element of fixed
order (as K varies). In the 1970's, Cohen and Lenstra observed
empirically that when the degree and signature of K is fixed, the
isomorphism class of C adheres to a natural probability distribution.
I'll discuss these Cohen-Lenstra heuristics and survey what is known,
2020 Nov 25

# Logic Seminar - Christian d'Elbée

11:15am to 1:00pm

## Location:

https://huji.zoom.us/j/82821066522?pwd=aVJnTkxBYktycHdzNFN5WDV0R2FkZz09

Dp-minimal integral domains.
2020 Dec 02

# Graduate student seminar - Danil Akhtyamoff, Alon Dogon and Yael Hacohen

4:00pm to 6:00pm

First Talk: 16:00-17:00

Danil Akhtyamoff and Alon Dogon: On uniform Hilbert Schmidt stability of groups
2020 Dec 29

# Dynamics seminar: Nattalie Tamam (UCSD) Effective equidistribution of horospherical flows in infinite volume

6:00pm to 7:00pm

Abstract: Horospherical flows in homogeneous spaces have been studied intensively over the last several decades and have many surprising applications in various fields. Many basic results are under the assumption that the volume of the space is finite, which is crucial as many basic ergodic theorems fail in the setting of an infinite measure space.In the talk we will discuss the infinite volume setting, and specifically, when can we expect horospherical orbits to equidistribute.
2020 Dec 07

# Combinatorics: Louis Theran (St Andrews)

11:00am to 1:00pm

## Location:

https://huji.zoom.us/j/86409334597?pwd=M0dBNDA5My9iY0tFbW93Y2t6NnQ5Zz09

HUJI Combinatorics Seminar

When: Monday Dec 7th, 2020, at 11AM

Speaker: Louis Theran (St. Andrews)

Title:  Unlabelled rigidity problems

Abstract:
2021 Jan 11

# Combinatorics: Oleg Pikhurko (Warwick)

11:00am to 1:00pm

## Location:

https://huji.zoom.us/j/83506273905?pwd=c0FhZk96bGRiYmR1OGlWUlloSi9TZz09

HUJI Combinatorics Seminar

When: Monday Jan 11th, 2021, at 11AM

Speaker: Oleg Pikhurko (Warwick)

Title: Asymptotic Structure for the Clique Density Theorem

Abstract:
2020 Dec 28

# Combinatorics: Semyon Alesker (TAU)

11:00am to 1:00pm

## Location:

https://huji.zoom.us/j/82014375680?pwd=RU1hMFBsZ2JHeFhicDBGVWR3MGtVdz09

HUJI Combinatorics Seminar

When: Monday Dec 28th, 2020, at 11AM

https://huji.zoom.us/j/82014375680?pwd=RU1hMFBsZ2JHeFhicDBGVWR3MGtVdz09

Speaker: Semyon Alesker (TAU)

Title: New inequalities on mixed volumes of convex bodies and valuations on convex sets.

Abstract:
2020 Dec 14

# Combinatorics: Natan Rubin (BGU)

11:00am to 1:00pm

2020 Nov 30

# Combinatorics: Ehud Friedgut (Weizmann)

11:00am to 1:00pm

## Location:

https://huji.zoom.us/j/85226464650?pwd=Tk13TEtEekJVMklUWWNnTjhlOGdNUT09

HUJI Combinatorics Seminar

When: Monday Nov 30th, 2020 11AM

Speaker: Ehud Friedgut (Weizmann)

Title:  A quest for Hyper Regular Graphs

Abstract:
2021 Jan 18

# Combinatorics: Shinichi Tanigawa

11:00am to 1:00pm

## Location:

https://huji.zoom.us/j/81176578450?pwd=TStYWHhhWnE3YkNuR0RlZmkrejBIUT09

HUJI Combinatorics Seminar

When: Monday Jan 18th, 2021, at 11AM (Israel time)

Speaker: Shin-ichi Tanigawa (University of Tokyo)

Title: Maximal Matroid Problem on Graphs

Abstract:
2021 Jan 04

# Combinatorics: Shoham Letzter (UCL)

11:00am to 1:00pm

## Location:

https://huji.zoom.us/j/88114702258?pwd=SllxczVjQTJLV0w1TkZFQjBUSGx6dz09

HUJI Combinatorics Seminar

When: Monday Jan 4th, 2021, at 11AM