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

# Special Analysis Seminar: Eitan Tadmor (Maryland)

2:00pm to 3:00pm

## Location:

Sprinzak Building, room 26
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

# Analysis Seminar: Lior Alon (Technion) "A central limit type conjecture for the nodal statistics of quantum graphs"

12:00pm to 1:00pm

## Location:

Ross 70
Title: A central limit type conjecture for the nodal statistics of quantum graphs Abstract:
2018 Dec 26

# CS theory seminar: Avi Wigderson (IAS) : An invitation to Invariant Theory

## Lecturer:

Avi Wigderson (IAS)
10:30am to 12:00pm

## Location:

Rothberg (CS building) B-220

### Theory of Computer Science Seminar

This talk provides a gentle, high level introduction to (the beautiful) Invariant Theory, that is aimed at non-experts. It will describe some of its main objects, problems and results.

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.
2018 Dec 31

# Combinatorics: Zur Luria (JCE) "On the threshold for simple connectivity in random 2-complexes"

11:00am to 1:00pm

## Location:

CS bldg, room B500, Safra campus Givat Ram
Speaker: Zur Luria, JCE Title: On the threshold for simple connectivity in random 2-complexes Abstract:
2018 Dec 24

# Combinatorics: Benny Sudakov, ETH, TBA

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. The systematic study of the above question was recently initiated by
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