2018 Dec 27

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

4:00pm to 5:00pm


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 Mar 20

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

12:00pm to 1:00pm


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.
2018 Dec 25

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

1:00pm to 2:00pm


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


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 24

Combinatorics: Benny Sudakov, ETH, TBA

11:00am to 1:00pm


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
2019 Jan 10

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

4:00pm to 5:15pm


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


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