Events & Seminars

2017 Nov 01

Logic Seminar - Immanuel BenPorat - "Cardinal conditions for strong Fubini theorems"

11:00am to 1:00pm

Location: 

Math209
This talk will be largely based on a paper by Joseph Shipman with the same title. We will discuss some variations of Fubini type theorems. The focus will be on what is known as "strong Fubini type theorems". Apparently these versions were proved to be independent of ZFC,and our main aim will be to sketch a proof of this result. We will assume basic knowledge in measure theory. Aside from that, the material is rather self contained.
2017 Jul 10

Special logic seminar - Noa Lavi, "Independent chapters in dependent theories"

11:00am to 1:00pm

Location: 

Ross 70
This talk is about three published papers of mine that form my phd. In the first two chapters I focus in the model theory of real closed fields and in the third one I take one step back and investigate in greater genearility dependent theories. The results are the following: 1. Boundedness criterion for rational functions over generalized semi-algebraic sets in real closed fields. 2. Positivity criterion for polynomials over generalized semi-algebraic sets in real closed valued fields.
2017 Nov 29

Logic Seminar - Isabel Muller - "Zil'bers Conjecture and Building-like Geometries"

11:00am to 1:00pm


In an attempt to classify the geometries arising in strongly minimal sets, Zil'ber conjectured them to split into three different types: Trivial geometries, vector space-like geometries and field-like geometries. Soon after, Hrushovski refuted this conjecture while introducing a new construction method, which has been modified and used a lot ever since.
2017 Apr 19

Logic seminar- Shimon Garti, "Forcing axioms and saturated ideals"

4:00pm to 6:00pm

Location: 

Ross 70
Abstract: Paul Larson proved that under Martin's axiom and large continuum there are no Laver ideals over aleph_1. He asked about weakly Laver ideals under some forcing axiom. We shall address two issues: 1. Under Martin's axiom and the continuum is above aleph_2, there are no weakly Laver ideals over aleph_1.. 2. Under Baumgartner's axiom, the parallel of Larson's theorem holds for ideals over aleph_2.
2016 Dec 19

Special logic seminar - Elad Levi "Algebraic regularity lemma for hypergraphs"

10:00am to 12:00pm

Location: 

Sprinzak 101
Speaker: Elad Levi Algebraic regularity lemma for hypergraphs Abstract: Szemer´edi’s Regularity Lemma is a fundamental tool in graph theory. It states that for every large enough graph, the set of vertices has a partition A1,..,Ak, such that for almost every two subsets Ai,Aj the induced bipartite graph on (Ai,Aj) is regular, i.e. similar to a random bipartite graph up to a given error.
2017 Dec 07

Combinatorics: Shira Zerbib Gelaki (MSRI, U. Michigan) "Colorful coverings of polytopes -- the hidden topological truth behind different colorful phenomena"

12:00pm to 1:00pm

Location: 

Room 101 in Sprinzak
Speaker: Shira Zerbib Gelaki (MSRI, University of Michigan) Title: Colorful coverings of polytopes -- the hidden topological truth behind different colorful phenomena Abstract: The topological KKMS Theorem is a powerful extension of the Brouwer's Fixed-Point Theorem, which was proved by Shapley in 1973 in the context of game theory. We prove a colorful and polytopal generalization of the KKMS Theorem, and show that our theorem implies some seemingly unrelated results in discrete geometry and combinatorics involving colorful settings.
2016 Nov 28

NT&AG: Boris Zilber (University of Oxford), "On algebraically closed field of characteristic 1"

2:00pm to 3:00pm

Location: 

Ros Building, 70A
Abstract: I will start with a motivation of what algebraic (and model-theoretic) properties an algebraically closed field of characteristic 1 is expected to have. Then I will explain how these properties can be obtained by the well-known in model theory Hrushovski's construction and then formulate very precise axioms that such a field must satisfy. The axioms have a form of statements about existence of solutions to systems of equations in terms of a 'multi-dimansional' valuation theory and the validity of these statements is an open problem to be discussed.
2017 Apr 03

NT&AG: Izzet Coskun (University of Illinois at Chicago), "Birational geometry of moduli spaces of sheaves on surfaces"

4:00pm to 5:00pm

Location: 

Tel Aviv University, Schreiber building, 209
Abstract: In the last five years Bridgeland stability has revolutionized our understanding of the geometry of moduli spaces of sheaves on surfaces, allowing us to compute ample and effective cones and describe different birational models. In this talk, I will survey some of my joint work with Daniele Arcara, Aaron Bertram, Jack Huizenga and Matthew Woolf on the birational geometry of moduli spaces of sheaves on the plane. I will describe the ample and effective cones of these moduli spaces, concentrating on Hilbert schemes of points and concrete examples.
2015 Dec 22

Number theory: Alexei Entin (Stanford) "Monodromy of Hurwitz spaces and extensions of F_q(t)"

10:30am to 11:45am

Location: 

Ross Building, room 70A
Hurwitz spaces are moduli spaces for extensions of curves with prescribed ramification types. They arise naturally when enumerating extensions of global function fields and also in many other contexts. The classical Hurwitz space H_{m,n} may be viewed as a finite cover of the space of n-sets of points on P^1. We will show that this cover has a big monodromy group for n>4. This can be applied to study the statistics of extensions of F_q(t) with varying branching locus in the large q limit. Joint work with Chris Hall and Robert Guralnick.
2017 Dec 25

NG&AT: Avner Segal (UBC) "Poles of the Standard L-function and Functorial Lifts for G2"

3:00pm to 4:00pm

Location: 

Room 70A, Ross Building, Jerusalem, Israel
The functoriality conjecture is a key ingredient in the theory of automorphic forms and the Langlands program. Given two reductive groups G and H, the principle of functoriality asserts that a map r:H^->G^ between their dual complex groups should naturally give rise to a map r*:Rep(H)->Rep(G) between their automorphic representations. In this talk, I will describe the idea of functoriality, its connection to L-functions and recent work on weak functorial lifts to the exceptional group of type G_2.
2016 Mar 17

Number theory

Repeats every week every Thursday until Thu Jun 16 2016 except Thu Apr 14 2016.
12:00pm to 1:15pm

12:00pm to 1:15pm
12:00pm to 1:15pm
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12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm

Location: 

Ross Building, room 63, Jerusalem, Israel
In his investigation of modular forms of half-integral weight, Shimura established, using Hecke theory, a family of relations between eigneforms of half-integral weight k+1/2 with a given level 4N and character chi and cusp forms of weight 2k and character chi^2. The level being subsequently determined by Niwa to be at most 2N.
2017 Feb 27

NT&AG: Stephen Lichtenbaum (Brown University), "A conjectured cohomological description of special values of zeta-functions"

2:00pm to 3:00pm

Location: 

Ross 70A
Abstract: Let X be a regular scheme, projective and flat over Spec Z. We give a conjectural formula in terms of motivic cohomology, singular cohomology and de Rham cohomology for the special value of the zeta-function of X at any rational integer. We will explain how this reduces to the standard formula for the residue of the Dedekind zeta-function at s = 1. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts.
2017 Nov 06

NT&AG: Walter Gubler (University of Regensburg), "The non-archimedean Monge-Ampère problem"

2:00pm to 3:00pm

Location: 

Ros 70
Abstract: Calabi conjectured that the complex Monge-Ampère equation on compact Kaehler manifolds has a unique solution. This was solved by Yau in 1978. In this talk, we present a non-archimedean version on projective Berkovich spaces. In joint work with Burgos, Jell, Künnemann and Martin, we improve a result of Boucksom, Favre and Jonsson in the equicharacteristic 0 case. We give also a result in positive equicharacteristic using test ideals.

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