2019
Apr
02

# Eventss

2019
Mar
18

# NT & AG - Antoine Ducros (Sorbonne Université), "Non-standard analysis and non-archimedean geometry"

2:30pm to 3:30pm

## Location:

Room 70A, Ross Building, Jerusalem, Israel

There is a general slogan according to which the limit behaviour of a one-parameter family of complex algebraic varieties when the parameter t tends to zero should be (partially) encoded in the associated t-adic analytic space in the sense of Berkovich; this slogan has given rise to deep and fascinating conjecturs by Konsevich and Soibelman, as well as positive results by various authors (Berkovich, Nicaise, Boucksom, Jonsson...).

2019
Mar
13

2019
May
22

# Set Theory Seminar - Gabriel Fernandes (BIU) (part II)

2:00pm to 3:30pm

## Location:

Ross 63

Abstract: We combine a technique of Steel with one due to Jensen and Steel to

obtain a core model below singular cardinals kappa which are

sufficiently closed under the beth function, assuming that there is no

premouse of height kappa with unboundedly many Woodin cardinals.

The motivation for isolating such core model is computing a lower bound for the strength of

the theory: T = ''ZFC + there is a singular cardinal kappa such that the set of ordinals below kappa where GCH holds is stationary and co-stationary''.

obtain a core model below singular cardinals kappa which are

sufficiently closed under the beth function, assuming that there is no

premouse of height kappa with unboundedly many Woodin cardinals.

The motivation for isolating such core model is computing a lower bound for the strength of

the theory: T = ''ZFC + there is a singular cardinal kappa such that the set of ordinals below kappa where GCH holds is stationary and co-stationary''.

2019
May
15

# Set Theory Seminar - Gabriel Fernandes (BIU): Local core models with more Woodin cardinals

2:00pm to 3:30pm

## Location:

Ross 63

Abstract: We combine a technique of Steel with one due to Jensen and Steel to

obtain a core model below singular cardinals kappa which are

sufficiently closed under the beth function, assuming that there is no

premouse of height kappa with unboundedly many Woodin cardinals.

The motivation for isolating such core model is computing a lower bound for the strength of

the theory: T = ''ZFC + there is a singular cardinal kappa such that the set of ordinals below kappa where GCH holds is stationary and co-stationary''.

obtain a core model below singular cardinals kappa which are

sufficiently closed under the beth function, assuming that there is no

premouse of height kappa with unboundedly many Woodin cardinals.

The motivation for isolating such core model is computing a lower bound for the strength of

the theory: T = ''ZFC + there is a singular cardinal kappa such that the set of ordinals below kappa where GCH holds is stationary and co-stationary''.

2019
Mar
12

# T&G: John Pardon (Princeton), Structural results in wrapped Floer theory

1:00pm to 2:30pm

## Location:

Room 110, Manchester Building, Jerusalem, Israel

I will discuss results relating different partially wrapped Fukaya categories. These include a K\"unneth formula, a `stop removal' result relating partially wrapped Fukaya categories relative to different stops, and a gluing formula for wrapped Fukaya categories. The techniques also lead to generation results for Weinstein manifolds and for Lefschetz fibrations. The methods are mainly geometric, and the key underlying Floer theoretic fact is an exact triangle in the Fukaya category associated to Lagrangian surgery along a short Reeb chord at infinity.

2019
Apr
01

# Combinatorics: Raphy Yuster (U. Haifa) "On some Ramsey type problems in tournaments"

11:00am to 1:00pm

## Location:

CS B-500, Safra campus

Speaker: Raphy Yuster, U. Haifa

Title: On some Ramsey type problems in tournaments

Abstract:

I will talk about several Ramsey type problems in tournaments guaranteeing the existence of subgraphs with certain chromatic properties.

Here are two such problems which attracted some attention recently:

1. Let g(n) be the smallest integer such that every tournament with more than g(n) vertices has an *acyclic subgraph* with chromatic number larger than n.

Title: On some Ramsey type problems in tournaments

Abstract:

I will talk about several Ramsey type problems in tournaments guaranteeing the existence of subgraphs with certain chromatic properties.

Here are two such problems which attracted some attention recently:

1. Let g(n) be the smallest integer such that every tournament with more than g(n) vertices has an *acyclic subgraph* with chromatic number larger than n.

2019
Mar
18

# Combinatorics: Arindam Banerjee (RMVERI), TBA

11:00am to 1:00pm

## Location:

CS B-500, Safra campus

Speaker: Arindam Banerjee, RMVERI

Title: Castelnuovo-Mumford Regularity, Combinatorics and Edge Ideals.

Abstract:

Title: Castelnuovo-Mumford Regularity, Combinatorics and Edge Ideals.

Abstract:

2019
Jun
17

# NO seminar: mini conference in memory of Prof. Yossi Zaks at U. Haifa

11:00am to 1:00pm

## Location:

U. Haifa

From Raphy Yuster: On Monday 17 June, 2019 we will hold a one day mini conference in memory of Professor Yossi Zaks

(see attached poster or updated information in

http://sciences.haifa.ac.il/math/wp/?page_id=1382 )

Mini conference: Yossi Zaks Memorial Meeting – Monday, June 17, 2019

list of speakers

Noga Alon, Princeton University and Tel Aviv University

Gil Kalai, Hebrew University

Nati Linial, Hebrew University

Rom Pinchasi, The Technion

Organizers

2019
Apr
29

# Combinatoric: Karthik C. Srikanta (Weizmann Institute) "On Closest Pair Problem and Contact Dimension of a Graph"

11:00am to 1:00pm

## Location:

CS B-500, Safra campus

Speaker: Karthik C. Srikanta (Weizmann Institute)

Title: On Closest Pair Problem and Contact Dimension of a Graph

Abstract: Given a set of points in a metric space, the Closest Pair problem asks to find a pair of distinct points in the set with the smallest distance. In this talk, we address the fine-grained complexity of this problem which has been of recent interest. At the heart of all our proofs is the construction of a family of dense bipartite graphs with special embedding properties and are inspired by the construction of locally dense codes.

Title: On Closest Pair Problem and Contact Dimension of a Graph

Abstract: Given a set of points in a metric space, the Closest Pair problem asks to find a pair of distinct points in the set with the smallest distance. In this talk, we address the fine-grained complexity of this problem which has been of recent interest. At the heart of all our proofs is the construction of a family of dense bipartite graphs with special embedding properties and are inspired by the construction of locally dense codes.

2019
Apr
08

# Combinatorics: Kim Minki (Technion) "The fractional Helly properties for families of non-empty sets"

11:00am to 1:00pm

## Location:

CS B-500, Safra campus

Speaker: Kim Minki, Technion

Title: The fractional Helly properties for families of non-empty sets

Abstract:

Let $F$ be a (possibly infinite) family of non-empty sets.

The Helly number of $F$ is defined as the greatest integer $m = h(F)$ for which there exists a finite subfamily $F'$ of cardinality $m$ such that every proper subfamily of $F'$ is intersecing and $F'$ itself is not intersecting.

For example, Helly's theorem asserts that the family of all convex sets in $d$-dimensional Euclidean space has Helly number $d+1$.

Title: The fractional Helly properties for families of non-empty sets

Abstract:

Let $F$ be a (possibly infinite) family of non-empty sets.

The Helly number of $F$ is defined as the greatest integer $m = h(F)$ for which there exists a finite subfamily $F'$ of cardinality $m$ such that every proper subfamily of $F'$ is intersecing and $F'$ itself is not intersecting.

For example, Helly's theorem asserts that the family of all convex sets in $d$-dimensional Euclidean space has Helly number $d+1$.

2019
Mar
25

# Combinatorics: Roy Meshulam (Technion) "Topology and combinatorics of the complex of flags"

11:00am to 1:00pm

## Location:

CS B-500, Safra campus

Speaker: Roy Meshulam (Technion)

Title: Topology and combinatorics of the complex of flags

Abstract:

Title: Topology and combinatorics of the complex of flags

Abstract:

2019
May
20

2019
Apr
15

# Combinatorics: problem session

11:00am to 1:00pm

## Location:

CS B-500, Safra campus

Speaker: Eyal Karni, BIU
Title: Combinatorial high dimensional expanders
Abstract:
An eps-expander is a graph G=(V,E) in which every set of vertices X where |X|<=|V|/2 satisfies |E(X,X^c)|>=eps*|X| . There are many edges that "go out" from any relevant set.

2019
Mar
07

# Special Ergodic Theory Day

(All day)