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

# Logic Seminar - Saharon Shelah

11:00am to 1:00pm

## Location:

Ross 63

Understanding $P(κ)/[κ]^{κ}$
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''.
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''.
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. It is straightforward that Omega(n) <= g(n) <= n^2. An improvement of both bounds is presented.
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:
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 ) Speakers: Noga Alon (Princeton and Tel Aviv University) Gil Kalai (Hebrew University) Nati Linial (Hebrew University) Rom Pinchasi (Technion) Schedule: 10:00-10:15 Greetings 10:15-11:05 Noga Alon 11:05-11:25 Coffee break 11:25-12:15 Gil Kalai 12:15-14:00 Lunch break to attendees (catering) 14:00-14:50 Nati Linial
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.
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 $d+1$.
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:
2019 May 20

# Combinatorics: Rom Pinchasi (Technion) TBA

11:00am to 1:00pm

## Location:

CS B-500, Safra campus
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

1:30pm to 2:30pm

Ross 70
2019 Mar 07

# Alexandre Danilenko (ILTPE) Forcing conservativeness of nonsingular Bernoulli shifts.

4:15pm to 5:15pm

Abstract: We first survey a recent progress related to the nonsingular Bernoulli transformations. Then we construct inductively new examples of conservative Bernoulli maps of type III. They appear as a limit of a sequence of Bernoulli maps of type II_1.