2017
Dec
25

# Combinatorics Seminar: Yuval Peres

11:00am to 12:30pm

## Location:

Room 130 at the IIAS

Title: Trace reconstruction for the deletion channel

Edmond J. Safra Campus The Hebrew University of Jerusalem

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2017
Dec
25

11:00am to 12:30pm

Room 130 at the IIAS

Title: Trace reconstruction for the deletion channel

2017
Jan
23

11:00am to 1:00pm

Rothberg B220 (CS bldg)

Speaker: Elchanan Mossel (MIT)

Title: Lower Bounds on Same-Set Inner Product in Correlated Spaces

Abstract: Suppose we pick X uniformly from {0,1,2}^n and Y is picked by letting each Y(i) = X(i) or

X(i) + 1 mod 3 with probability 0.5 each independently.

Is it true that for every set S with |S| > c 2^n it holds that the probability that both X and Y are in S is at least g(c) > 0, where g does not depend on the dimension n?

Similar questions were asked before in different contexts. For example,

Title: Lower Bounds on Same-Set Inner Product in Correlated Spaces

Abstract: Suppose we pick X uniformly from {0,1,2}^n and Y is picked by letting each Y(i) = X(i) or

X(i) + 1 mod 3 with probability 0.5 each independently.

Is it true that for every set S with |S| > c 2^n it holds that the probability that both X and Y are in S is at least g(c) > 0, where g does not depend on the dimension n?

Similar questions were asked before in different contexts. For example,

2017
May
29

11:00am to 1:00pm

Rothberg B220 (CS bldg)

Speaker: Dmitry Faifman (U Toronto)

Title: The integral geometry of indefinite signature.

Title: The integral geometry of indefinite signature.

2016
Nov
21

11:00am to 1:00pm

B220 Rothberg (CS)

Speaker: David Ellis, Queen Mary

Title: Some applications of the $p$-biased measure to Erd\H{o}s-Ko-Rado type problems

Abstract:

Title: Some applications of the $p$-biased measure to Erd\H{o}s-Ko-Rado type problems

Abstract:

2018
Jan
08

11:00am to 12:30pm

Eilat Hall at IIAS

There are exponentially many triangulations of a fixed manifold extremely distant from each other in some natural metric. I will discuss similar results for contractible 2-complexes. In order to prove these for the manifold being the sphere (or a contractible complex) one needs to create topology out of nothing. This is done by studying group theory of the trivial group.

2017
Jan
09

11:00am to 1:00pm

Rothberg B220 (CS bldg)

Speaker: Ilan Karpas, HU

Tilte: Families with forbidden intersection patterns

Abstract:

Let l, n be even natural numbers. A pattern p of length l is an element

p = (p1, . . . , pl) ∈ {−, +}^l. Given such a pattern and two sets A, B ⊂ [n], we say that the pair (A, B) forms pattern p if the following conditions are satisfied:

1. A \Delta B = {i_1, . . . , i_l}, where i_1 < i_2 < . . . < i_l,

2. For 1 ≤ j ≤ l, we have i_ j ∈ A \ B if p_ j = + and i_ j ∈ B \ A if p_ j = −.

Tilte: Families with forbidden intersection patterns

Abstract:

Let l, n be even natural numbers. A pattern p of length l is an element

p = (p1, . . . , pl) ∈ {−, +}^l. Given such a pattern and two sets A, B ⊂ [n], we say that the pair (A, B) forms pattern p if the following conditions are satisfied:

1. A \Delta B = {i_1, . . . , i_l}, where i_1 < i_2 < . . . < i_l,

2. For 1 ≤ j ≤ l, we have i_ j ∈ A \ B if p_ j = + and i_ j ∈ B \ A if p_ j = −.

2018
Jan
01

11:00am to 12:30pm

2017
May
07

11:00am to 1:00pm

2016
Nov
07

10:40am to 12:50pm

Israel Institute for Advanced Studies, Safra campus, Givat Ram

* This talk is joint with the 20th Midrasha Mathematicae: 60 faces to groups, celebrating Alex Lubotzky's 60th birthday.

The full program for AlexFest, Nov. 6--11, is detailed here:

http://www.as.huji.ac.il/ias/public/121/the20thMidrashaMa2016/program.pdf

-----------

Speaker: László Babai (University of Chicago)

Title: Finite permutation groups and the Graph Isomorphism problem

Updated abstract:

The Graph Isomorphism (GI) problem is the algorithmic problem

The full program for AlexFest, Nov. 6--11, is detailed here:

http://www.as.huji.ac.il/ias/public/121/the20thMidrashaMa2016/program.pdf

-----------

Speaker: László Babai (University of Chicago)

Title: Finite permutation groups and the Graph Isomorphism problem

Updated abstract:

The Graph Isomorphism (GI) problem is the algorithmic problem

2017
Dec
18

11:00am to 12:30pm

Eilat Hal at IIAS

Title: Polynomials vanishing on Cartesian products

Abstract:

Let F(x,y,z) be a real trivariate polynomial of constant degree, and let A,B,C be three sets of real numbers, each of size n. How many roots can F have on A x B x C?

2017
Jan
02

11:00am to 1:00pm

Rothberg B220 (CS)

Speaker: Ron Holzman, Technion

Title: Edge-covers in d-interval hypergraphs

Title: Edge-covers in d-interval hypergraphs

2018
Jan
22

11:00am to 12:30pm

Room 130, Feldman Building

Title: Shellability is NP-complete

2017
Mar
20

11:00am to 1:00pm

Rothberg B220 (CS bldg)

Speaker: Doron Puder, TAU

Title: Meanders and Non-Crossing Partitions

Abstract: Imagine a long river and a closed (not self-intersecting) racetrack that crosses the river by bridges 2n times. This is called a meander. How many meanders are there with 2n bridges (up to homeomorphisms of the plane that stabilizes the river)? This challenging question, which is open for several decades now, has connections to several fields of mathematics.

Title: Meanders and Non-Crossing Partitions

Abstract: Imagine a long river and a closed (not self-intersecting) racetrack that crosses the river by bridges 2n times. This is called a meander. How many meanders are there with 2n bridges (up to homeomorphisms of the plane that stabilizes the river)? This challenging question, which is open for several decades now, has connections to several fields of mathematics.

2016
Jun
16

11:00am to 12:00pm

Rothberg A410

Speaker: Bram Petri, Max Planck Institute, Bonn

Title: The length spectrum of a random surface

Title: The length spectrum of a random surface

2017
Nov
13

11:00am to 12:30pm

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