2020 Jul 20

# Combinatorics: Daniel Kalmanovich (HUJI)

2:00pm to 4:00pm

## Location:

Zoom
Speaker: Daniel Kalmanovich (HUJI)
2020 Jul 06

# Combinatorics: Xinyu Wu (CMU)

2:00pm to 4:00pm

Speaker: Xinyu Wu (CMU)
Title: Explicit near-fully X-Ramanujan graphs
Abstract:
In this talk I will introduce constructions of finite graphs which resemble some given infinite graph both in terms of their local neighborhoods, and also their spectrum.
2020 Jul 13

# Combinatorics: Edinah K. Gnang (JHU)

2:00pm to 4:00pm

## Location:

Zoom
Speaker: Edinah K. Gnang (JHU)
Title: On the Kotzig-Ringel-Rosa conjecture
Abstract:
In this talk we describe and motivate the K.R.R. conjecture and describe a functional graph theoretic approach enabling us to tackle the K.R.R. conjecture via a composition lemma.
2020 Jun 24

# Logic Seminar - Jorge Cely

11:00am to 1:00pm

## Location:

Zoom - ID: 995 8999 9308 Password: 568039
Jorge Cely will speak about the fundamental lemma for spherical Hecke algebras and motivic integration.

Abstract:
2020 Jun 30

# Tsviqa Lakrec (HUJI). Affine Random Walks on the Torus

2:00pm to 3:00pm

Abstract: I will discuss a quantitative equidistribution result for the random walk on a torus arising from the action of the group of affine transformations. This is a joint work with Weikun He and Elon Lindenstrauss.

2020 Jun 23

# Dalia Terhesiu (Leiden) Mixing rates for Infinite horizon Lorentz maps

2:00pm to 3:00pm

Abstract: I will report on recent results on sharp error rates in the local limit theorem for the Sinai billiard map (one and two dimensional) with infinite horizon. This is joint work with F. Pene. This result allows to also obtain higher order terms and thus, sharp mixing rates in the speed of mixing of dynamically Hölder observables for the planar and tubular infinite horizon Lorentz gases in the map (discrete time) case.

Join Zoom Meeting
Meeting ID: 917 3652 5930
2020 Jun 18

# Colloquium: Nati Linial (HUJI) - Hypertrees

2:30pm to 3:30pm

## Location:

https://huji.zoom.us/j/93456379511?pwd=OHFOZEFJZDIrckx5V01PMnZGRk1wQT09
Meeting ID: 934 5637 9511

Title: Hypertrees
2020 Jun 16

# John Griesmer (Colorado School of Mines) Separating Bohr denseness from measurable recurrence

2:00pm to 3:00pm

Abstract: We construct a set which is dense in the Bohr topology on the group of integers and which is not a set of measurable recurrence, answering a question asked by Bergelson, Hegyvári, Ruzsa, and the author, in various combinations.  This talk will provide a broad overview and explain details of the construction. We will see similarities to many other examples in additive combinatorics and ergodic theory, such as Igor Kriz's construction showing topological recurrence does not imply measurable recurrence, and Ruzsa's niveau sets.
2020 Jun 10

# Logic Seminar - Kobi Peterzil

11:00am to 1:00pm

## Location:

Zoom - ID: 951 5522 0236 Password: 387201

Kobi Peterzil will speak about the infinitesimal subgroup of a simple real Lie group.
(w. Martin Bays)

Abstrract:

A theorem with Pillay and Starchenko (2000) says that If G is a simple linear Lie group then the pure group (G,.) is either:

(i) unstable, and then bi-interpretable with the real field, e.g when G is compact,
or
(ii) stable, and then bi-interpretable with the complex field.
2020 Jun 09

# Weikun He (HUJI), Equidistribution of linear random walks on the torus.

2:00pm to 3:00pm

Abstract: Quantitative equidistribution for linear random walks on the torus was first obtained by Bourgain, Furman, Lindenstrauss and Mozes. In this talk I will present a recent progress where the proximality assumption in their result is relaxed. I will also discuss an application to expansion in groups. This is based on a joint work with Nicolas de Saxcé.

2020 Jun 24

# Analysis Seminar: Angkana Rüland (Heidelberg) "Microstructure in Shape-Memory Alloys: Rigidity, Flexibility and Some Numerical Simulations"

12:00pm to 1:00pm

## Location:

zoom

Title: Microstructure in Shape-Memory Alloys: Rigidity,Flexibility and Some Numerical Simulations

Abstract: In this talk I will discuss a striking dichotomy whichoccurs in the mathematical analysis of microstructures in shape-memory alloys:On the one hand, some models for these materials display a very rigid structurewith only very specific microstructures, if one assumes that surface energiesare penalised. On the other hand, without this penalisation, for the samemodels a plethora of very wild'' solutions exists.

2020 Jun 24

# Amitsur Memorial Symposium 2020 (on Zoom)

(All day)

## Location:

Zoom

The Amitsur Memorial Symposium is an annual conference in memory of Prof. Shimshon Avraham Amitsur. It is hosted by a different institution each year since 1995.

The 27th Amitsur Memorial Symposium was originally planned to take place on the grounds of the Open University of Israel in Raanana. Instead, due to the COVID-19 pandemic, it will be held online on June 24th and 25th, 17:00–20:30

2020 Jun 01

# Fabien Pazuki [HUJI-BGU AGNT Seminar]

2:15pm to 4:00pm

Title: Regulators of number fields and abelian varieties.
2020 Jun 22

# Combinatorics: Lukas Kuhne (HUJI)

11:00am to 1:00pm

Speaker: Lukas Kuhne (HUJI)

Title:  Matroids doing Algebra

Abstract:

A matroid  is a combinatorial object based on an abstraction of linear independence in vector spaces and forests in graphs. It is a classical question to determine whether a given matroid is representable as a vector configuration over a field. Such a matroid is called linear.
2020 Jun 04

# מפגשי מתעניינים לתואר שני

## Lecturer:

Prof. Michael Hochman ; Orna Barak
11:00am

## Location:

Zoom
חושבים על תואר שני? מתלבטים על מסלול כלשהו? רוצים לדעת יותר, מה זה בכלל אומר ללמוד כאן לתואר שני?
אז אל דאגה, אנחנו יודעים שיש הרבה שאלות. לכן ריכזנו במיוחד עבורך את כל מפגשי המתעניינים שלנו בזום, סביב המסלולים השונים והחוגים.

מפגשי התעניינות ב-ZOOM לתואר שני במתמטיקה יהיו:
ב-3.6.2020 בשעה 14:00
ב-4.6.2020 בשעה 11:00
נשמח לראותך!