2018 Dec 24

# Combinatorics: Benny Sudakov (ETH) "Subgraph statistics"

11:00am to 1:00pm

## Location:

Rothberg CS room B500, Safra campus, Givat Ram
Speaker: Benny Sudakov, ETH, Zurich
Title: Subgraph statistics
Abstract:
Consider integers $k,\ell$ such that $0\le \ell \le \binom{k}2$. Given
a large graph $G$, what is the fraction of $k$-vertex
subsets of $G$ which span exactly $\ell$ edges? When $G$ is empty or
complete, and $\ell$ is zero or $\binom k 2$,
this fraction can be exactly 1. On the other hand if $\ell$ is not one
these extreme values, then by Ramsey's theorem, this
fraction is strictly smaller than 1.
2018 Dec 17

# Combinatorics: Wojciech Samotij (TAU) "Subsets of posets minimising the number of chains"

11:00am to 1:00pm

## Location:

Rothberg CS bldg, room B500, Safra campus, Givat Ram
Speaker: Wojciech Samotij, TAU
Title: Subsets of posets minimising the number of chains
Abstract:
2019 Jan 10

# Joram Seminar: Larry Guth (MIT) - Restriction theory and wave packets

4:00pm to 5:15pm

## Location:

Manchester Building (Hall 2), Hebrew University Jerusalem
The proof of decoupling grew out of an area of Fourier analysis called restriction theory. In this talk, we will describe some of the basic problems and tools of restriction theory, especially wave packets, which are a crucial idea in the proof of decoupling.
2018 Dec 17

# NT & AG - Sazzad Biswas

2:30pm to 3:30pm

## Location:

Ross 70

Title: Local root numbers for Heisenberg representations

Abstract: On the Langlands program, explicit computation of the local root numbers
(or epsilon factors) for Galois representations is an integral part.
But for arbitrary Galois representation of higher dimension, we do not
have explicit formula for local root numbers. In our recent work
(joint with Ernst-Wilhelm Zink) we consider Heisenberg representation
(i.e., it represents commutators by scalar matrices) of the Weil
2018 Dec 13

# Basic Notions: Sergiu Hart - "Game Dynamics and Equilibria"

4:00pm to 5:00pm

## Location:

Ross 70
The general theme is game dynamics leading to equilibrium concepts.
The plan is to deal with the following topics (all concepts will be defined, and proofs / proof outlines will be provided):
(1) An integral approach to the construction of calibrated forecasts and their use for Nash equilibrium dynamics.
(2) Blackwell's Approachability Theorem and its use for correlated equilibrium dynamics (regret-matching).
(3) Communication complexity and its use for the speed of convergence of uncoupled dynamics.
2018 Dec 20

# Basic Notions: Sergiu Hart - "Game Dynamics and Equilibria"

4:00pm to 5:00pm

## Location:

Ross 70
The general theme is game dynamics leading to equilibrium concepts.
The plan is to deal with the following topics (all concepts will be defined, and proofs / proof outlines will be provided):
(1) An integral approach to the construction of calibrated forecasts and their use for Nash equilibrium dynamics.
(2) Blackwell's Approachability Theorem and its use for correlated equilibrium dynamics (regret-matching).
(3) Communication complexity and its use for the speed of convergence of uncoupled dynamics.
2018 Dec 05

# Eshnav: Prof. Tamar Ziegler: Surprises in large subsets

## Lecturer:

Prof. Tamar Ziegler
6:45pm to 7:30pm

## Location:

Manchester House, Lecture Hall 2

## פרופ' תמר ציגלר : אילו הפתעות יש בתתי קבוצות גדולות?

מה ניתן למצוא בתתי קבוצות גדולות של מרחב וקטורי V מעל שדה סופי?
ישנו עיקרון יפה הנקרא עקרון רמזי, לפיו בתתי קבוצות גדולות של קבוצה עם מבנה ניתן למצוא ״תת מבנה״.
נדון בשאלות - כמה גדולה יכולה להיות תת קבוצה מקסימלית של V שלא מכילה ישר? מישור?

הדלקת נרות בשעה 17:45
הרצאת אשנב בשעה 18:30

2018 Dec 04

# T&G: Pierrick Bousseau (ETH - ITS), Quivers and curves

2:00pm to 3:30pm

## Location:

Room 209, Manchester Building, Jerusalem
I will talk about old and new results relating curve counting on complex surfaces and quiver representations.
2018 Dec 26

# Set Theory Seminar - Ur Yaar (The Modal Logic of Forcing)

2:00pm to 3:30pm

## Location:

Ross 63
Title: The Modal Logic of Forcing

Abstract: Modal logic is used to study various modalities, i.e. various ways in which statements can be true, the most notable of which are the modalities of necessity and possibility. In set-theory, a natural interpretation is to consider a statement as necessary if it holds in any forcing extension of the world, and possible if it holds in some forcing extension. One can now ask what are the modal principles which captures this interpretation, or in other words - what is the "Modal Logic of Forcing"?
2019 Jan 02

2:00pm to 3:30pm

Ross 63
2018 Dec 03

# NT & AG - Zev Rosengarten

2:30pm to 3:30pm

## Location:

Ross 70
Title: Tamagawa Numbers of Linear Algebraic Groups III: Exotic Groups
2018 Dec 10

# NT & AG - Sazzad Biswas

2:30pm to 3:30pm

## Location:

Ross 70

Title: Local root numbers for Heisenberg representations

Abstract: On the Langlands program, explicit computation of the local root numbers
(or epsilon factors) for Galois representations is an integral part.
But for arbitrary Galois representation of higher dimension, we do not
have explicit formula for local root numbers. In our recent work
(joint with Ernst-Wilhelm Zink) we consider Heisenberg representation
(i.e., it represents commutators by scalar matrices) of the Weil
2018 Dec 06

# Basic notions - Tamar Ziegler "Gower’s proof for 4-term arithmetic progressions in subsets of integers of positive density"

4:00pm to 5:00pm

Abstract: we give an overview of Gowers' proof for the existence of 4-term progression in subsets of positive density in the integers. We will discuss the tools from additive combinatorics that are used in the proof as well as some related conjectures.
2018 Nov 29

# Basic notions - Tamar Ziegler "Gower’s proof for 4-term arithmetic progressions in subsets of integers of positive density"

4:00pm to 5:00pm

Abstract: we give an overview of Gowers' proof for the existence of 4-term progression in subsets of positive density in the integers. We will discuss the tools from additive combinatorics that are used in the proof as well as some related conjectures.
2019 Jan 16

2:00pm to 4:00pm

Sprinzak 102
tba