Seminars

2018 Oct 22

NT & AG Lunch: Jasmin Matz "Modular forms"

1:00pm to 2:00pm

Location: 

Faculty lounge, Math building
Abstract: Modular forms are historically the first example of automorphic forms, and are still studied today as they have many applications. In this talk I want to introduce modular forms, give some examples, and, if time permits, explain the connection to elliptic curves, objects we already met in the first lecture.
2018 Oct 24

Analysis Seminar: Boaz Slomka (WIS) "An improved bound for Hadwiger’s covering problem via thin shell inequalities for the convolution square"

12:00pm to 1:00pm

Location: 

Room 70, Ross building
Title: An improved bound for Hadwiger’s covering problem via thin shell inequalities for the convolution square. Abstract: A long-standing open problem, known as Hadwiger’s covering problem, asks what is the smallest natural number N(n) such that every convex body in {\mathbb R}^n can be covered by a union of the interiors of at most N(n) of its translates. Despite continuous efforts, the best-known general upper bound for this number remain as it was more than half a decade ago, and is of the order of \binom{2n}{n}n\ln n.
2018 Oct 25

Basic Notions Seminar: Ehud de Shalit - Periods and Hodge theory, complex and p-adic P-adic theory

4:00pm to 5:15pm

Location: 

Ross 70
Speaker: Ehud de Shalit
Title:Periods and Hodge theory, complex and p-adic
P-adic theory
p-adic Hodge theory started with Tate in the 1960's, and witnessed two periods of great expansion: one by Fontaine and his school, the other one more recently, by Scholze and his collaborators. It has found spectacular applications in arithmetic algebraic geometry. Scholze got the Fields medal last August for this work. By analogy with the first lecture we shall try to explain the main ideas, without going into details



2018 Oct 18

Basic Notions Seminar: Periods and Hodge theory, complex and p-adic

4:15pm to 5:30pm

Speaker: Ehud de Shalit
Title:Periods and Hodge theory, complex and p-adic
Complex theory
This will be a survey of complex Hodge theory, with applications to period maps and moduli and with an emphasis on the example of abelian varieties. It will cover classical results of Riemann, Siegel, Hodge and Griffiths
2018 Oct 15

NT & AG Lunch: Yakov Varshavsky "Mathematics around Langlands program"

1:00pm to 2:00pm

Location: 

Faculty lounge, Math building

This is a new seminar, whose official name is "Topics in number theory
and algebraic geometry". At least in the beginning the goal
of the seminar will be to give a (relatively) gentle introduction to
various topics, which should be accessible to beginning but motivated graduate students.
The seminar has a number in the shnaton (80942), so graduate students
can get a credit for it.
First talk: The goal of this organizational/introductory talk will be to
describe areas of mathematics, connected to Langlands program.
2018 Dec 09

Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

12:00pm to 2:00pm

Location: 

Ross 70A
Abstract: The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation. We shall present the classical methid, and give an approachable introduction to Kim's method. I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html
2018 Oct 08

T&G: Stephan Rosebrock (Karlsruhe), Asphericity, Relative Asphericity and Labelled Oriented Trees

12:30pm to 2:00pm

Location: 

Room 70, Ross Building, Jerusalem, Israel
The Whitehead conjecture asks whether a subcomplex of an aspherical 2-complex is always aspherical. This question is open since 1941. Howie has shown that the existence of a finite counterexample implies (up to the Andrews-Curtis conjecture) the existence of a counterexample within the class of labelled oriented trees. Labelled oriented trees are algebraic generalisations of Wirtinger presentations of knot groups.
2018 Nov 18

Special Analysis Seminar: Sergey Denisov (Wisconsin) "Szego theorem for measures on the real line: optimal results and applications"

12:00pm to 1:00pm

Location: 

Manchester building, room 209
Title: Szego theorem for measures on the real line: optimal results and applications. Abstract: Measures on the unit circle for which the logarithmic integral converges can be characterized in many different ways: e.g., through their Schur parameters or through the predictability of the future from the past in Gaussian stationary stochastic process. In this talk, we consider measures on the real line for which logarithmic integral exists and give their complete characterization in terms of the Hamiltonian in De Branges canonical system. This provides a generalization of the
2018 Oct 29

Combinatorics: Noam Lifshitz, BIU, "Sharp thresholds for sparse functions with applications to extremal combinatorics."

11:00am to 1:00pm

Location: 

Rothberg CS blgd, room B500, Safra campus, Givat, Ram
Speaker: Noam Lifshitz, BIU Title: Sharp thresholds for sparse functions with applications to extremal combinatorics. Abstract: The sharp threshold phenomenon is a central topic of research in the analysis of Boolean functions. Here, one aims to give sufficient conditions for a monotone Boolean function $f$ to satisfy $\mu_{p}(f)=o(\mu_{q}(f))$, where $q = p + o(p)$, and $\mu_{p}(f)$ is the probability that $f=1$ on an input with independent coordinates, each taking the value $1$ with probability $p$.
2018 Oct 15

Combinatorics: Tammy Ziegler, HU, "Extending weakly polynomial functions from high rank varieties"

11:00am to 1:00pm

Location: 

Rothberg CS building, room B500, Safra campus, Givat Ram
Speaker: Tammy Ziegler, HU Title: Extending weakly polynomial functions from high rank varieties Abstract: Let k be a field, V a k-vector space, X in V a subset. Say that f: X —> k is weakly polynomial of degree a if its restriction to any isotropic subspace is a polynomial degree of a. We show that if X is a high rank variety then any weakly polynomial function of degree a is the restriction to X of a polynomial of degree a on V. Joint work with D. Kazhdan.
2018 Nov 05

Combinatorics: Ohad Klein, BIU, "Biased halfspaces, noise sensitivity, and local Chernoff inequalities"

11:00am to 1:00pm

Location: 

Rothberg CS bldg, room B500, Safra campus, Givat Ram
Speaker: Ohad Klein, BIU Title: Biased halfspaces, noise sensitivity, and local Chernoff inequalities Abstract: Let X be a random variable defined by X=\sum_i a_i x_i where x_i are independent random variables uniformly distributed in \{-1, 1\}, and a_i in R, the reals. Assume Var(X)=1=sum a_{i}^2. We investigate the tail behavior of the variable X, and apply the results to study halfspace functions f:{-1,1}^{n}-->{-1,1} defined by f(x)=1 (\sum_i a_i x_i > t) for some t in R. A puzzle: Let a = max_{i} |a_{i}|. Is it true that Pr[|X| \leq a] \geq a/10?

Pages