2018 Dec 19

# Set Theory Seminar - Asaf Karagila (The Morris model)

2:00pm to 3:30pm

## Location:

Ross 63
Title: The Morris model
Abstract: Douglass Morris was a student of Keisler, and in 1970 he announced the
following result: It is consistent with ZF that for every \alpha, there is a set
A_\alpha which is the countable union of countable sets, and the power set of
A_\alpha can be partitioned into \aleph_\alpha non-empty sets.
The result was never published, and survived only in the form of a short
announcement and an exercise in Jech's "The Axiom of Choice". We go over the
proof of this theorem using modern tools, as well as some of its odd
2019 Jan 10

# Joram Seminar: Decoupling and harmonic analysis

## Lecturer:

Larry Guth (MIT), Lev Buhovski (Tel Aviv University)
(All day)

2019 May 16

# Landau Lectures: Luc Illusie (University of Paris-Sud)

Thu, 16/05/2019 (All day) to Tue, 21/05/2019 (All day)

2018 Dec 10

# Erdős Lectures: Igor Pak (UCLA)

Mon, 10/12/2018 (All day) to Thu, 13/12/2018 (All day)

2018 Oct 31

2:00pm to 3:29pm

2018 Oct 29

# NT&AG: Michael Temkin (HUJI), ""Differential forms on Berkovich curves"

2:30pm to 3:30pm

## Location:

Room 70A, Ross Building, Jerusalem, Israel

2018 Oct 24

# Set Theory Seminar (Ross 63)

2:00pm to 3:30pm

## Location:

Ross 63

לאירוע הזה יש שיחת וידאו.
(US) +1 225-434-0384 קוד גישה: 826117698#
2018 Dec 18

# Dynamics Lunch: Omer Ben-Neria "Dichotomies for Borel equivalence relations"

12:00pm to 1:00pm

Abstract:
We would like present several results in descriptive set theory involving definable equivalence relations on Polish spaces.
Given an equivalence relation E on a polish space X, we would like to study the classification problem of determining whether two objects x,y in X are E-related.
2018 Nov 06

# Jon Aaronson (TAU) On the bounded cohomology of actions of multidimensional groups.

2:15pm to 3:15pm

Although each cocycle for a action of the integers is
specified by the sequence of Birkhoff sums of a function,
it is relatively difficult to specify cocycles for the actions of
multidimensional groups such as $\Bbb Z^2$.
We'll see that if $(X,T)$ is a transitive action of the finitely
generated (countable) group $\Gamma$ by homeomorphism of the polish space $X$,
and $\Bbb B$ is a separable Banach space, there is a cocycle
$F:\Gamma\times X \to\Bbb B$
with each $x\mapsto F(g,x)$ bounded and continuous
2018 Nov 04

# Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

12:00pm to 2:00pm

## Location:

Ross 70A
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html
2018 Nov 18

# Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

## Location:

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebra
2019 Jan 06

# Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

## Location:

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebra
2018 Nov 18

# Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

12:00pm to 2:00pm

## Location:

Ross 70A
Abstract:
The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation.
We shall present the classical methid, and give an approachable introduction to Kim's method.
I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html
2018 Dec 02

# Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

## Location:

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity.
Recommended prerequisites: basic commutative algebra