2019
Jan
01

# Seminars

2019
Feb
20

# Analysis Seminar: Itay Londner (UBC) "Interpolation sets and arithmetic progressions"

12:00pm to 1:00pm

## Location:

Ross 70

Title: Interpolation sets and arithmetic progressions
Abstract: Given a set S of positive measure on the unit circle, a set of integers K is an interpolation set (IS) for S if for any data {c(k)} in l^2(K) there exists a function f in L^2(S) such that its Fourier coefficients satisfy f^(k)=c(k) for all k in K.
In the talk I will discuss the relationship between the concept of IS and the existence arithmetic structure in the set K, I will focus primarily on the case where K contains arbitrarily long arithmetic progressions with specified lengths and step sizes.

2019
Jan
06

# GT&ME: Olga Gorelkina (University of Liverpool Management School) - "Collusion via Information Sharing and Optimal Auctions"

2:00pm to 3:30pm

Refreshments available at 1:30.

This paper studies collusion via information sharing in the context of auctions. The model of collusion via

This paper studies collusion via information sharing in the context of auctions. The model of collusion via

2018
Dec
30

# GT & ME: Rida Laraki (CNRS, Liverpool) - "Majority judgment: a new voting method" (joint with Michel Balinski)

2:00pm to 3:30pm

## Location:

Elath Hall, 2nd floor, Feldman Building, Edmond Safra Campus

Refreshments available at 1:30 p.m.

2019
Jan
01

# Yotam Smilansky (HUJI), Multiscale substitution schemes and Kakutani sequences of partitions.

2:15pm to 3:15pm

## Location:

Ross 70

Abstract: Substitution schemes provide a classical method for constructing tilings
of Euclidean space. Allowing multiple scales in the scheme, we introduce
a rich family of sequences of tile partitions generated by the substitution
rule, which include the sequence of partitions of the unit interval
considered by Kakutani as a special case. In this talk we will use new path counting
results for directed weighted graphs to show that such sequences
of partitions are uniformly distributed, thus extending Kakutani's
original result. Furthermore, we will describe certain limiting frequencies

2018
Dec
27

# 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.

2019
Jan
03

# Basic Notions: Dorit Aharonov - "Quantum computation"

4:00pm to 5:00pm

## Location:

Ross 70

Quantum computation
==================
You can hardly open the newspaper nowadays without seeing something about Quantum computation. But aside from the hype and the industry interest, this deceivingly simple model offers a surprisingly rich set of mathematical, physical and conceptual questions, which seem to touch upon almost any area of mathematics: from group representations, to Markov chains, Knot invariants, expanders, cryptography, lattices, differential geometry, and many more.
I will give some definitions, provide some basic results, and sketch some open problems.

2019
Jan
09

2019
Mar
20

# Analysis Seminar: Andrei Osipov (Yale) "On the evaluation of sums of periodic Gaussians"

12:00pm to 1:00pm

## Location:

Ross 70

Title:
On the evaluation of sums of periodic Gaussians
Abstract:
Discrete sums of the form
$\sum_{k=1}^N q_k \cdot \exp\left( -\frac{t – s_k}{2 \cdot \sigma^2} \right)$
where $\sigma>0$ and $q_1, \dots, q_N$ are real numbers and
$s_1, \dots, s_N$ and $t$ are vectors in $R^d$,
are frequently encountered in numerical computations across a variety of fields.
We describe an algorithm for the evaluation of such sums under periodic boundary conditions, provide a rigorous error analysis, and discuss its implications on the computational cost and choice of parameters.

2019
May
29

2018
Dec
25

# Ofer Shwartz (Weizmann) Convergence along the cutting-sequences of the geodesic flow

2:15pm to 3:15pm

## Location:

Ross 70

The geodesic flow on a normal cover of a compact hyperbolic surface admits a "random walk" on the group of decks transformations $G$. In this talk, I'll provide some recent results which connect this walk to the geometric properties of the cover and $G$.

2018
Dec
25

# T&G: Or Hershkovits (Stanford), Mean Curvature Flow of Surfaces -- NOTE special time and location

1:00pm to 2:00pm

## Location:

Room 70, Ross Building, Jerusalem, Israel

In the last 35 years, geometric flows have proven to be a powerful tool in geometry and topology. The Mean Curvature Flow is, in many ways, the most natural flow for surfaces in Euclidean space. In this talk, which will assume no prior knowledge, I will illustrate how mean curvature flow could be used to address geometric questions.

2019
Jan
11

# Joram Seminar: Lev Buhovski (Tel-Aviv University) - 0,01% Improvement of the Liouville property for discrete harmonic functions on Z^2.

11:45am to 12:45pm

## Location:

Manchester Building (Hall 2), Hebrew University Jerusalem

Let u be a harmonic function on the plane. The Liouville theorem claims that if |u| is bounded on the whole plane, then u is identically constant. It appears that if u is a harmonic function on the lattice Z^2, and |u| < 1 on 99,99% of Z^2, then u is a constant function. Based on a joint work with A. Logunov, Eu. Malinnikova and M. Sodin.

2019
Jan
11

# Joram Seminar: Larry Guth (MIT) - On the proof of decoupling II

10:15am to 11:15am

## Location:

Manchester Building (Hall 2), Hebrew University Jerusalem

Second talk out of two on the proof - the first talk can be found here. Read more about Joram Seminar: Larry Guth (MIT) - On the proof of decoupling II

2019
Jan
11

# Joram Seminar: Larry Guth (MIT) - On the proof of decoupling I

9:00am to 10:00am

## Location:

Manchester Building (Hall 2), Hebrew University Jerusalem

First talk out of two on the proof - the second talk can be found here. Read more about Joram Seminar: Larry Guth (MIT) - On the proof of decoupling I