2019 Jun 05

# Logic Seminar - Oren Kalish

11:00am to 1:00pm

## Location:

Ross 63

Tight weakly o-minimal structures

We introduce a class of weakly o-minimal expansions of groups, called tight structures. We prove that the o-minimal completion of a tight structure is linearly bounded.
2019 May 22

# Logic Seminar - Shahar Oriel

11:00am to 1:00pm

## Location:

Ross 63
An omega-categorical strictly stable pseudo-plane

Lachlan conjectured that any omega-categorical stable theory is even omega-stable. Later in 1980 it was shown that there is no omega-categorical omega-stable pseudo plane. In 1988, Hrushovski refuted Lachlan's conjecture by constructing an omega-categorical, strictly stable pseudo-plane.

We will give a quick overview of the construction and try to use this example to test if some properties of omega-categorical  omega-stable theories lift to omega-categorical stable theories.
2019 Mar 18

# Special course: A. Goncharov (Yale, visiting Einstein Institute of Mathematics) "Quantum geometry of moduli spaces of local systems on surfaces and representation theory"

Repeats every week every Monday until Mon Apr 29 2019 except Mon Apr 22 2019.
4:00pm to 6:00pm

4:00pm to 6:00pm
4:00pm to 6:00pm
4:00pm to 6:00pm
4:00pm to 6:00pm
4:00pm to 6:00pm

## Location:

Ross 70
Abstract. This is a joint work with Linhui Shen. A decorated surface is an oriented surface with punctures and a finite collection of special points on the boundary, considered modulo isotopy. Let G be a split adjoint group. We introduce a moduli space Loc(G,S) of G-local systems on a decorated surface S, which reduces to the character variety when S has no boundary, and quantize it.
2019 Mar 18

# NT & AG Lunch: Ehud DeShalit "An overview of class field theory"

1:00pm to 2:00pm

## Location:

Faculty lounge, Math building
Class field theory classifies abelian extensions of local and global fields in terms of groups constructed from the base. We shall survey the main results of class field theory for number fields and function fields alike. The goal of these introductory lectures is to prepare the ground for the study of explicit class field theory in the function field case, via Drinfeld modules. I will talk for the first 2 or 3 times.
2019 Apr 02

# Dynamics lunch: Lauritz Streck "A rigidity sequence construction on the circle"

12:00pm to 1:00pm

## Location:

Manchester faculty club
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 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 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 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 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 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 ) 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 Raphael Yuster, University of Haifa