2018
Mar
22

# Eventss

2018
Jun
04

# Combinatorics: Lior Gishboliner (TAU) "A Generalized Turan Problem and Its Applications"

11:00am to 12:30pm

## Location:

IIAS, room 130, Feldman Building, Givat Ram

Speaker: Lior Gishboliner, Tel Aviv University

Title: A Generalized Turan Problem and Its Applications

Title: A Generalized Turan Problem and Its Applications

2018
Apr
11

# Analysis Seminar: Cy Maor (Toronto) "The geodesic distance on diffeomorphism groups"

12:00pm to 1:00pm

## Location:

Ross Building, Room 70

Since the seminal work of Arnold on the Euler equations (1966), many equations in hydrodynamics were shown to be geodesic equations of diffeomorphism groups of manifolds, with respect to various Sobolev norms. This led to new ways to study these PDEs, and also initiated the study of of the geometry of those groups as (infinite dimensional) Riemannian manifolds.

2018
Apr
17

2018
May
14

# Combinatorics: Joel Friedman (UBC) "Open Problems Related to the Zeta Functions"

11:00am to 12:30pm

## Location:

IIAS, Eilat hall, Feldman bldg, Givat Ram

Speaker: Joel Friedman, UBC

Title: Open Problems Related to the Zeta Functions

Abstract:

We express some open problems in graph theory in terms of Ihara graph zeta

functions, or, equivalently, non-backtracking matrices of graphs. We focus

on "expanders" and random regular graphs, but touch on some seemingly

unrelated problems encoded in zeta functions.

We suggest that zeta functions of sheaves on graphs may have relevance to

complexity theory and to questions of Stark and Terras regarding whether

Title: Open Problems Related to the Zeta Functions

Abstract:

We express some open problems in graph theory in terms of Ihara graph zeta

functions, or, equivalently, non-backtracking matrices of graphs. We focus

on "expanders" and random regular graphs, but touch on some seemingly

unrelated problems encoded in zeta functions.

We suggest that zeta functions of sheaves on graphs may have relevance to

complexity theory and to questions of Stark and Terras regarding whether

2018
Apr
30

# Combinatorics: Michael Farber (Queen Mary), "Multi-parameter random simplicial complexes"

11:00am to 12:30pm

## Location:

IIAS Eilat hall, Feldman building, Givat Ram

Speaker: Michael Farber, Queen Mary

Title: Multi-parameter random simplicial complexes

2018
May
07

# Combinatorics: Zur Luria (ETH), "New bounds for the n-queen's problem"

11:00am to 12:30pm

## Location:

IIAS, Eilat hall, Feldman bldg, Givat Ram

Speaker: Zur Luria, ETH

Title: New bounds for the n-queen's problem

Abstract:

The famous n-queens problem asks: In how many ways can n nonattacking queens be placed on an n by n chessboard? This question also makes sense on the toroidal chessboard, in which opposite sides of the board are identified. In this setting, the n-queens problem counts the number of perfect matchings in a certain regular hypergraph. We give an extremely general bound for such counting problems, which include Sudoku squares and designs.

Title: New bounds for the n-queen's problem

Abstract:

The famous n-queens problem asks: In how many ways can n nonattacking queens be placed on an n by n chessboard? This question also makes sense on the toroidal chessboard, in which opposite sides of the board are identified. In this setting, the n-queens problem counts the number of perfect matchings in a certain regular hypergraph. We give an extremely general bound for such counting problems, which include Sudoku squares and designs.

2018
Apr
17

# Dynamics seminar: Elon Lindenstrauss (HUJI) - Symmetry of entropy in higher rank diagonalizable actions and measure classification

2:15pm to 3:15pm

## Location:

Ross 70

The miracle of entropy - that the entropy of a measure preserving transformation calculated forward in time (for T) and backwards in time (for T^{-1}) are equal - is, depending on point of view and the definition used, either a triviality or highly surprising. Entropy theory (of Z-actions) plays a key role in analyzing the rigidity of algebraic (diagonalizable) Z^k actions; I show how a strong version of this symmetry property of entropy is useful in studying the measure classification question for such actions.

Joint work with Manfred Einsiedler.

2018
Mar
27

2018
Mar
19

2018
Apr
24

# T&G: Anton Khoroshkin (HSE), Compactified moduli spaces of rational curves with marked points as homotopy quotients of operads

1:00pm to 2:30pm

## Location:

Room 63, Ross Building, Jerusalem, Israel

I will explain the notion of a homotopy quotient of an operad providing different examples of operads of compactified moduli spaces of genus zero curves with marked points: including the space of complex curves (math.arXiv:1206.3749), the real loci of the complex one (arXiv:math/0507514) and the noncommutative …

2018
Apr
10

# T&G: Jesse Kass (University of South Carolina), How to count lines on a cubic surface arithmetically

1:00pm to 2:30pm

## Location:

Room 110, Manchester Building, Jerusalem, Israel

Salmon and Cayley proved the celebrated 19th century result that a smooth cubic surface over the complex numbers contains exactly 27 lines. By contrast, the count over the real numbers depends on the surface, and these possible counts were classified by Segre. A number of researchers have recently made the striking observation that Segre’s work shows a certain signed count is always 3. In my talk, I will explain how to extend this result to an arbitrary field.

1997
Dec
18

# Zabrodsky Lectures: Prof. Robert Oliver (Paris-Nord)

4:00pm to 5:30pm

# Zabrodsky Lectures: Prof. Robert Oliver (Paris-Nord)

2000
Dec
07