Events & Seminars

2018 Jun 18

Combinatorics -- Erdos lecture cancelled; instead (NOTE THE TIME!) :

10:30am to 12:30pm


IIAS, Eilat hall, Feldman bldg (top floor), Givat Ram
Speaker: Ilan Newman and Yuri Rabinovich, U.Haifa Title: Sparsifiers - Part I (Part II from 2pm to 4pm, same day and place) Abstract: Time permitting, we plan to discuss the following topics (in this order): 1. * Additive Sparsification and VC dimension * Multiplicative Sparsification * Examples: cut weights, cut-dimension of L_1 metrics, general metrics, and their high-dimensional analogues 2. * Multiplicative Sparsification and Triangular Rank; * Karger-Benczur sparsification of cuts weights 3. * Batson-Spielman-Srivastava sparsification
2018 Jun 25

Combinatorics: Roman Glebov (HU) "Perfect Matchings in Random Subgraphs of Regular Bipartite Graphs"

11:00am to 12:30pm


IIAS, room 130, Feldman bldg, Givat Ram
Speaker: Roman Glebov (HU) Title: Perfect Matchings in Random Subgraphs of Regular Bipartite Graphs Abstract: Consider the random process in which the edges of a graph $G$ are added one by one in a random order. A classical result states that if $G$ is the complete graph $K_{2n}$ or the complete bipartite graph $K_{n,n}$, then typically a perfect matching appears at the moment at which the last isolated vertex disappears. We extend this result to arbitrary $k$-regular bipartite graphs $G$ on $2n$ vertices for all $k=\Omega(n)$.
2018 Apr 29

GAME THEORY AND MATHEMATICAL ECONOMICS RESEARCH SEMINAR:Michal Feldman, Tel Aviv University "Interdependent Values without Single-Crossing (Joint work with Alon Eden, Amos Fiat and Kira Goldner)"

1:30pm to 2:30pm


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


We consider a setting where an auctioneer sells a single item to n potential agents with {\em interdependent values}. That is, each agent has her own private signal, and the valuation of each agent is a function of all n private signals. This captures settings such as valuations for oil fields, broadcast rights, art, etc.

2018 Apr 25

Special Talk : Justin Noel (University of Regensburg) - "Blue-shift and thick tensor ideals"


Justin Noel (University of Regensburg)
2:30pm to 3:30pm


Shprinzak 27


I will discuss a recent generalization of Kuhn's Blue-shift theorem about Tate cohomology. Combining this result with work of Arone, Dwyer, and Lesh we resolve a conjecture of Balmer and Sanders and classify the thick tensor ideals of compact genuine $A$-spectra, where $A$ is a finite abelian group. This is joint work with Tobias Barthel, Markus Hausmann, Niko Naumann, Thomas Nikolaus, and Nathaniel Stapleton.

2018 May 08

Dynamics Seminar: Tsviqa Lakrec (Huji)

12:00pm to 1:00pm


Manchester 209
Consider a simple random walk on $\mathbb{Z}$ with a random coloring of $\mathbb{Z}$. Look at the sequence of the first $N$ steps taken and colors of the visited locations. From it, you can deduce the coloring of approximately $\sqrt{N}$ integers. Suppose an adversary may change $\delta N$ entries in that sequence. What can be deduced now? We show that for any $\theta<0.5,p>0$, there are $N_{0},\delta_{0}$ such that if $N>N_{0}$ and $\delta<\delta_{0}$ then with probability $>1-p$ we can reconstruct the coloring of $>N^{\theta}$ integers.
2018 Jun 19

Tomasz Rzepecki (Uniwersytet Wrocławski): Topological dynamics and Galois groups in model theory

2:15pm to 3:15pm


Ross 70
In recent years, topological dynamics have become an important tool in model theory. I will talk about some topological dynamical results from my PhD thesis about the so-called group-like equivalence relations. I plan to give a glimpse of the motivations in model theory (mostly related to the model-theoretic Galois groups and connected components of definable groups) and to show some ideas of the proofs. I will briefly recall the required notions from topological dynamics. Some knowledge of model theory will help to understand the motivations, but otherwise, it will not be necessary.
2018 May 29

Dynamics Lunch: Matan Seidel (Huji) - "The Mass Transport Principle in Percolation Theory"

12:00pm to 1:00pm


Manchester lounge
The Mass Transport Principle is a useful technique that was introduced to the study of automorphism-invariant percolations by Häggström in 1997. The technique is a sort of mass conservation principle, that allows us to relate random properties (such as the random degree of a vertex) to geometric properties of the graph. I will introduce the principle and the class of unimodular graphs on which it holds, as well as a few of its applications.